diff --git a/application/controllers/ChannelController.php b/application/controllers/ChannelController.php
index 163fcc26..6dc48e6a 100644
--- a/application/controllers/ChannelController.php
+++ b/application/controllers/ChannelController.php
@@ -6,44 +6,30 @@
 
 use Icinga\Module\Notifications\Common\Database;
 use Icinga\Module\Notifications\Forms\ChannelForm;
-use Icinga\Module\Notifications\Model\Channel;
 use Icinga\Web\Notification;
-use ipl\Sql\Connection;
-use ipl\Stdlib\Filter;
 use ipl\Web\Compat\CompatController;
 
 class ChannelController extends CompatController
 {
-    /** @var Connection */
-    private $db;
-
-    public function init()
+    public function init(): void
     {
         $this->assertPermission('config/modules');
-
-        $this->db = Database::get();
     }
 
-    public function indexAction()
+    public function indexAction(): void
     {
-        $channel = Channel::on($this->db);
         $channelId = $this->params->getRequired('id');
-
-        $channel->filter(Filter::equal('id', $channelId));
-
-        $channel = $channel->first();
-
-        $this->addTitleTab(sprintf(t('Channel: %s'), $channel->name));
-
-        $form = (new ChannelForm($this->db, $channelId))
-            ->populate($channel)
+        $form = (new ChannelForm(Database::get()))
+            ->loadChannel($channelId)
             ->on(ChannelForm::ON_SUCCESS, function (ChannelForm $form) {
                 if ($form->getPressedSubmitElement()->getName() === 'delete') {
+                    $form->removeChannel();
                     Notification::success(sprintf(
                         t('Deleted channel "%s" successfully'),
                         $form->getValue('name')
                     ));
                 } else {
+                    $form->editChannel();
                     Notification::success(sprintf(
                         t('Channel "%s" has successfully been saved'),
                         $form->getValue('name')
@@ -53,6 +39,8 @@ public function indexAction()
                 $this->redirectNow('__CLOSE__');
             })->handleRequest($this->getServerRequest());
 
+        $this->addTitleTab(sprintf(t('Channel: %s'), $form->getChannelName()));
+
         $this->addContent($form);
     }
 }
diff --git a/application/controllers/ChannelsController.php b/application/controllers/ChannelsController.php
index b55d1eda..90127d36 100644
--- a/application/controllers/ChannelsController.php
+++ b/application/controllers/ChannelsController.php
@@ -52,8 +52,9 @@ public function indexAction()
         $sortControl = $this->createSortControl(
             $channels,
             [
-                'name' => t('Name'),
-                'type' => t('Type')
+                'name'          => t('Name'),
+                'type'          => t('Type'),
+                'changed_at'    => t('Changed At')
             ]
         );
 
@@ -104,6 +105,7 @@ public function addAction()
         $this->addTitleTab(t('Add Channel'));
         $form = (new ChannelForm($this->db))
             ->on(ChannelForm::ON_SUCCESS, function (ChannelForm $form) {
+                $form->addChannel();
                 Notification::success(
                     sprintf(
                         t('New channel %s has successfully been added'),
diff --git a/application/controllers/ContactController.php b/application/controllers/ContactController.php
index 13f511d7..0fc7b429 100644
--- a/application/controllers/ContactController.php
+++ b/application/controllers/ContactController.php
@@ -15,51 +15,37 @@
 
 class ContactController extends CompatController
 {
-    /** @var Connection */
-    private $db;
-
-    public function init()
+    public function init(): void
     {
         $this->assertPermission('notifications/config/contacts');
-
-        $this->db = Database::get();
     }
 
-    public function indexAction()
+    public function indexAction(): void
     {
-        $contact = Contact::on($this->db);
         $contactId = $this->params->getRequired('id');
 
-        $contact->filter(Filter::equal('id', $contactId));
-
-        $contact = $contact->first();
-
-        $this->addTitleTab(sprintf(t('Contact: %s'), $contact->full_name));
-
-        $form = (new ContactForm($this->db, $contactId))
-            ->populate($contact)
+        $form = (new ContactForm(Database::get()))
+            ->loadContact($contactId)
             ->on(ContactForm::ON_SUCCESS, function (ContactForm $form) {
-                $form->addOrUpdateContact();
-                /** @var FieldsetElement $contactElement */
-                $contactElement = $form->getElement('contact');
+                $form->editContact();
                 Notification::success(sprintf(
                     t('Contact "%s" has successfully been saved'),
-                    $contactElement->getValue('full_name')
+                    $form->getContactName()
                 ));
 
                 $this->redirectNow('__CLOSE__');
             })->on(ContactForm::ON_REMOVE, function (ContactForm $form) {
                 $form->removeContact();
-                /** @var FieldsetElement $contactElement */
-                $contactElement = $form->getElement('contact');
                 Notification::success(sprintf(
                     t('Deleted contact "%s" successfully'),
-                    $contactElement->getValue('full_name')
+                    $form->getContactName()
                 ));
 
                 $this->redirectNow('__CLOSE__');
             })->handleRequest($this->getServerRequest());
 
+        $this->addTitleTab(sprintf(t('Contact: %s'), $form->getContactName()));
+
         $this->addContent($form);
     }
 }
diff --git a/application/controllers/ContactGroupController.php b/application/controllers/ContactGroupController.php
index 8b760ab1..b1c31aa4 100644
--- a/application/controllers/ContactGroupController.php
+++ b/application/controllers/ContactGroupController.php
@@ -7,7 +7,9 @@
 use Icinga\Module\Notifications\Common\Database;
 use Icinga\Module\Notifications\Common\Links;
 use Icinga\Module\Notifications\Forms\ContactGroupForm;
+use Icinga\Module\Notifications\Model\Contact;
 use Icinga\Module\Notifications\Model\Contactgroup;
+use Icinga\Module\Notifications\Model\ContactgroupMember;
 use Icinga\Module\Notifications\Widget\ItemList\ContactList;
 use Icinga\Web\Notification;
 use ipl\Html\Attributes;
@@ -44,7 +46,13 @@ public function indexAction(): void
 
         $this->addControl(new HtmlElement('div', new Attributes(['class' => 'header']), Text::create($group->name)));
 
-        $this->addControl($this->createPaginationControl($group->contact));
+        $contacts = Contact::on(Database::get())
+            ->filter(Filter::all(
+                Filter::equal('contactgroup_member.contactgroup_id', $groupId),
+                Filter::equal('contactgroup_member.deleted', 'n')
+            ));
+
+        $this->addControl($this->createPaginationControl($contacts));
         $this->addControl($this->createLimitControl());
 
         $this->addContent(
@@ -56,7 +64,7 @@ public function indexAction(): void
             ))->openInModal()
         );
 
-        $this->addContent(new ContactList($group->contact));
+        $this->addContent(new ContactList($contacts));
 
         $this->addTitleTab(t('Contact Group'));
         $this->setTitle(sprintf(t('Contact Group: %s'), $group->name));
@@ -90,12 +98,11 @@ public function editAction(): void
                 }
             })
             ->on(Form::ON_SUCCESS, function (ContactGroupForm $form) use ($groupId) {
-                if ($form->editGroup()) {
-                    Notification::success(sprintf(
-                        t('Successfully updated contact group %s'),
-                        $form->getValue('group_name')
-                    ));
-                }
+                $form->editGroup();
+                Notification::success(sprintf(
+                    t('Successfully updated contact group %s'),
+                    $form->getValue('group_name')
+                ));
 
                 $this->closeModalAndRefreshRemainingViews(Links::contactGroup($groupId));
             })
diff --git a/application/controllers/ContactGroupsController.php b/application/controllers/ContactGroupsController.php
index d37e7e29..feb22831 100644
--- a/application/controllers/ContactGroupsController.php
+++ b/application/controllers/ContactGroupsController.php
@@ -46,7 +46,8 @@ public function indexAction(): void
         $sortControl = $this->createSortControl(
             $groups,
             [
-                'name' => t('Group Name'),
+                'name'          => t('Group Name'),
+                'changed_at'    => t('Changed At')
             ]
         );
 
diff --git a/application/controllers/ContactsController.php b/application/controllers/ContactsController.php
index 7a65f7be..c6c3408d 100644
--- a/application/controllers/ContactsController.php
+++ b/application/controllers/ContactsController.php
@@ -50,7 +50,8 @@ public function indexAction()
         $sortControl = $this->createSortControl(
             $contacts,
             [
-                'full_name' => t('Full Name'),
+                'full_name'     => t('Full Name'),
+                'changed_at'    => t('Changed At')
             ]
         );
 
@@ -101,15 +102,15 @@ public function indexAction()
         $this->getTabs()->activate('contacts');
     }
 
-    public function addAction()
+    public function addAction(): void
     {
         $this->addTitleTab(t('Add Contact'));
 
         $form = (new ContactForm($this->db))
             ->on(ContactForm::ON_SUCCESS, function (ContactForm $form) {
-                $form->addOrUpdateContact();
+                $form->addContact();
                 Notification::success(t('New contact has successfully been added'));
-                $this->redirectNow(Url::fromPath('notifications/contacts'));
+                $this->redirectNow(Links::contacts());
             })->handleRequest($this->getServerRequest());
 
         $this->addContent($form);
diff --git a/application/controllers/EventRuleController.php b/application/controllers/EventRuleController.php
index f52b59ad..e331e3a2 100644
--- a/application/controllers/EventRuleController.php
+++ b/application/controllers/EventRuleController.php
@@ -10,7 +10,6 @@
 use Icinga\Module\Notifications\Forms\EventRuleForm;
 use Icinga\Module\Notifications\Forms\SaveEventRuleForm;
 use Icinga\Module\Notifications\Model\Incident;
-use Icinga\Module\Notifications\Model\ObjectExtraTag;
 use Icinga\Module\Notifications\Model\Rule;
 use Icinga\Module\Notifications\Web\Control\SearchBar\ExtraTagSuggestions;
 use Icinga\Module\Notifications\Widget\EventRuleConfig;
@@ -62,21 +61,9 @@ public function indexAction(): void
             );
         }
 
-        $disableRemoveButton = false;
-        if (ctype_digit($ruleId)) {
-            $incidents = Incident::on(Database::get())
-                ->with('rule')
-                ->filter(Filter::equal('rule.id', $ruleId));
-
-            if ($incidents->count() > 0) {
-                $disableRemoveButton = true;
-            }
-        }
-
         $saveForm = (new SaveEventRuleForm())
             ->setShowRemoveButton()
             ->setShowDismissChangesButton($cache !== null)
-            ->setRemoveButtonDisabled($disableRemoveButton)
             ->setSubmitButtonDisabled($cache === null)
             ->setSubmitLabel($this->translate('Save Changes'))
             ->on(SaveEventRuleForm::ON_SUCCESS, function ($form) use ($ruleId, $eventRuleConfig) {
@@ -151,7 +138,7 @@ public function indexAction(): void
     public function fromDb(int $ruleId): array
     {
         $query = Rule::on(Database::get())
-            ->withoutColumns('timeperiod_id')
+            ->columns(['id', 'name', 'object_filter'])
             ->filter(Filter::equal('id', $ruleId));
 
         $rule = $query->first();
@@ -161,12 +148,20 @@ public function fromDb(int $ruleId): array
 
         $config = iterator_to_array($rule);
 
-        foreach ($rule->rule_escalation as $re) {
+        $ruleEscalations = $rule
+            ->rule_escalation
+            ->withoutColumns(['changed_at', 'deleted']);
+
+        foreach ($ruleEscalations as $re) {
             foreach ($re as $k => $v) {
                 $config[$re->getTableName()][$re->position][$k] = $v;
             }
 
-            foreach ($re->rule_escalation_recipient as $recipient) {
+            $escalationRecipients = $re
+                ->rule_escalation_recipient
+                ->withoutColumns(['changed_at', 'deleted']);
+
+            foreach ($escalationRecipients as $recipient) {
                 $config[$re->getTableName()][$re->position]['recipient'][] = iterator_to_array($recipient);
             }
         }
@@ -248,7 +243,6 @@ public function editAction(): void
             ->setAction(Url::fromRequest()->getAbsoluteUrl())
             ->on(Form::ON_SUCCESS, function ($form) use ($ruleId, $cache, $config) {
                 $config['name'] = $form->getValue('name');
-                $config['is_active'] = $form->getValue('is_active');
 
                 if ($cache || $ruleId === '-1') {
                     $this->sessionNamespace->set($ruleId, $config);
diff --git a/application/controllers/EventRulesController.php b/application/controllers/EventRulesController.php
index a04cbc55..8e1a0e6d 100644
--- a/application/controllers/EventRulesController.php
+++ b/application/controllers/EventRulesController.php
@@ -51,7 +51,8 @@ public function indexAction(): void
         $sortControl = $this->createSortControl(
             $eventRules,
             [
-                'name' => t('Name'),
+                'name'          => t('Name'),
+                'changed_at'    => t('Changed At')
             ]
         );
 
diff --git a/application/controllers/ScheduleController.php b/application/controllers/ScheduleController.php
index 79fc1969..298a0159 100644
--- a/application/controllers/ScheduleController.php
+++ b/application/controllers/ScheduleController.php
@@ -68,7 +68,7 @@ public function settingsAction(): void
         $this->setTitle($this->translate('Edit Schedule'));
         $scheduleId = (int) $this->params->getRequired('id');
 
-        $form = new ScheduleForm();
+        $form = new ScheduleForm(Database::get());
         $form->setShowRemoveButton();
         $form->loadSchedule($scheduleId);
         $form->setSubmitLabel($this->translate('Save Changes'));
@@ -95,7 +95,7 @@ public function settingsAction(): void
     public function addAction(): void
     {
         $this->setTitle($this->translate('New Schedule'));
-        $form = (new ScheduleForm())
+        $form = (new ScheduleForm(Database::get()))
             ->setAction($this->getRequest()->getUrl()->getAbsoluteUrl())
             ->on(Form::ON_SUCCESS, function (ScheduleForm $form) {
                 $scheduleId = $form->addSchedule();
diff --git a/application/controllers/SchedulesController.php b/application/controllers/SchedulesController.php
index a9af10dc..9ee77003 100644
--- a/application/controllers/SchedulesController.php
+++ b/application/controllers/SchedulesController.php
@@ -32,7 +32,10 @@ public function indexAction(): void
         $limitControl = $this->createLimitControl();
         $sortControl = $this->createSortControl(
             $schedules,
-            ['schedule.name' => t('Name')]
+            [
+                'schedule.name' => t('Name'),
+                'changed_at'    => t('Changed At')
+            ]
         );
 
         $paginationControl = $this->createPaginationControl($schedules);
diff --git a/application/controllers/SourceController.php b/application/controllers/SourceController.php
index a84e9298..3c442fcc 100644
--- a/application/controllers/SourceController.php
+++ b/application/controllers/SourceController.php
@@ -14,7 +14,7 @@
 
 class SourceController extends CompatController
 {
-    public function init()
+    public function init(): void
     {
         $this->assertPermission('config/modules');
     }
@@ -23,38 +23,29 @@ public function indexAction(): void
     {
         $sourceId = (int) $this->params->getRequired('id');
 
-        /** @var ?Source $source */
-        $source = Source::on(Database::get())
-            ->filter(Filter::equal('id', $sourceId))
-            ->first();
-        if ($source === null) {
-            $this->httpNotFound($this->translate('Source not found'));
-        }
-
-        $form = (new SourceForm(Database::get(), $sourceId))
-            ->populate($source)
+        $form = (new SourceForm(Database::get()))
+            ->loadSource($sourceId)
             ->on(SourceForm::ON_SUCCESS, function (SourceForm $form) {
-                /** @var string $sourceName */
-                $sourceName = $form->getValue('name');
-
                 /** @var FormSubmitElement $pressedButton */
                 $pressedButton = $form->getPressedSubmitElement();
                 if ($pressedButton->getName() === 'delete') {
+                    $form->removeSource();
                     Notification::success(sprintf(
                         $this->translate('Deleted source "%s" successfully'),
-                        $sourceName
+                        $form->getSourceName()
                     ));
                 } else {
+                    $form->editSource();
                     Notification::success(sprintf(
                         $this->translate('Updated source "%s" successfully'),
-                        $sourceName
+                        $form->getSourceName()
                     ));
                 }
 
                 $this->switchToSingleColumnLayout();
             })->handleRequest($this->getServerRequest());
 
-        $this->addTitleTab(sprintf($this->translate('Source: %s'), $source->name));
+        $this->addTitleTab(sprintf($this->translate('Source: %s'), $form->getSourceName()));
         $this->addContent($form);
     }
 }
diff --git a/application/controllers/SourcesController.php b/application/controllers/SourcesController.php
index c7fdac02..65b831fc 100644
--- a/application/controllers/SourcesController.php
+++ b/application/controllers/SourcesController.php
@@ -40,8 +40,9 @@ public function indexAction(): void
         $sortControl = $this->createSortControl(
             $sources,
             [
-                'name' => t('Name'),
-                'type' => t('Type')
+                'name'          => t('Name'),
+                'type'          => t('Type'),
+                'changed_at'    => t('Changed At')
             ]
         );
 
@@ -93,9 +94,8 @@ public function addAction(): void
     {
         $form = (new SourceForm(Database::get()))
             ->on(SourceForm::ON_SUCCESS, function (SourceForm $form) {
-                /** @var string $sourceName */
-                $sourceName = $form->getValue('name');
-                Notification::success(sprintf(t('Added new source %s has successfully'), $sourceName));
+                $form->addSource();
+                Notification::success(sprintf(t('Added new source %s successfully'), $form->getSourceName()));
                 $this->switchToSingleColumnLayout();
             })
             ->handleRequest($this->getServerRequest());
diff --git a/application/forms/ChannelForm.php b/application/forms/ChannelForm.php
index d1ab6f0d..f710de4a 100644
--- a/application/forms/ChannelForm.php
+++ b/application/forms/ChannelForm.php
@@ -4,8 +4,11 @@
 
 namespace Icinga\Module\Notifications\Forms;
 
+use Icinga\Exception\Http\HttpNotFoundException;
 use Icinga\Module\Notifications\Model\Channel;
 use Icinga\Module\Notifications\Model\AvailableChannelType;
+use Icinga\Module\Notifications\Model\Contact;
+use Icinga\Module\Notifications\Model\RuleEscalationRecipient;
 use Icinga\Web\Session;
 use ipl\Html\Contract\FormSubmitElement;
 use ipl\Html\FormElement\BaseFormElement;
@@ -13,6 +16,7 @@
 use ipl\I18n\GettextTranslator;
 use ipl\I18n\StaticTranslator;
 use ipl\Sql\Connection;
+use ipl\Stdlib\Filter;
 use ipl\Validator\EmailAddressValidator;
 use ipl\Web\Common\CsrfCounterMeasure;
 use ipl\Web\Compat\CompatForm;
@@ -43,14 +47,14 @@ class ChannelForm extends CompatForm
     /** @var array<string, mixed> */
     private $defaultChannelOptions = [];
 
-    public function __construct(Connection $db, ?int $channelId = null)
+    public function __construct(Connection $db)
     {
         $this->db = $db;
-        $this->channelId = $channelId;
     }
 
     protected function assemble()
     {
+        $this->addAttributes(['class' => 'channel-form']);
         $this->addElement($this->createCsrfCounterMeasure(Session::getSession()->getId()));
 
         $this->addElement(
@@ -110,6 +114,18 @@ protected function assemble()
         );
 
         if ($this->channelId !== null) {
+            $isInUse = Contact::on($this->db)
+                ->columns('1')
+                ->filter(Filter::equal('default_channel_id', $this->channelId))
+                ->first();
+
+            if ($isInUse === null) {
+                $isInUse = RuleEscalationRecipient::on($this->db)
+                    ->columns('1')
+                    ->filter(Filter::equal('channel_id', $this->channelId))
+                    ->first();
+            }
+
             /** @var FormSubmitElement $deleteButton */
             $deleteButton = $this->createElement(
                 'submit',
@@ -117,7 +133,14 @@ protected function assemble()
                 [
                     'label'          => $this->translate('Delete'),
                     'class'          => 'btn-remove',
-                    'formnovalidate' => true
+                    'formnovalidate' => true,
+                    'disabled'       => $isInUse !== null,
+                    'title'          => $isInUse
+                        ? $this->translate(
+                            "Channel is still referenced as a contact's default"
+                            . " channel or in an event rule's escalation"
+                        )
+                        : null
                 ]
             );
 
@@ -152,48 +175,80 @@ public function hasBeenSubmitted()
         return parent::hasBeenSubmitted();
     }
 
-    public function populate($values)
+    /**
+     * Load the channel with given id
+     *
+     * @param int $id
+     *
+     * @return $this
+     *
+     * @throws HttpNotFoundException
+     */
+    public function loadChannel(int $id): self
     {
-        if ($values instanceof Channel) {
-            $values = [
-                'name'      => $values->name,
-                'type'      => $values->type,
-                'config'    => json_decode($values->config, true) ?? []
-            ];
-        }
-
-        parent::populate($values);
+        $this->channelId = $id;
+        $this->populate($this->fetchDbValues());
 
         return $this;
     }
 
-    protected function onSuccess()
+    /**
+     * Add the new channel
+     */
+    public function addChannel(): void
     {
-        if ($this->getPressedSubmitElement()->getName() === 'delete') {
-            $this->db->delete('channel', ['id = ?' => $this->channelId]);
+        $channel = $this->getValues();
 
-            return;
-        }
+        $channel['config'] = json_encode($this->filterConfig($channel['config']));
+        $channel['changed_at'] = time() * 1000;
+
+        $this->db->insert('channel', $channel);
+    }
+
+    /**
+     * Edit the channel
+     *
+     * @return void
+     */
+    public function editChannel(): void
+    {
+        $this->db->beginTransaction();
 
         $channel = $this->getValues();
-        $config = array_filter(
-            $channel['config'],
-            function ($configItem, $key) {
-                if (isset($this->defaultChannelOptions[$key])) {
-                    return $this->defaultChannelOptions[$key] !== $configItem;
-                }
+        $storedValues = $this->fetchDbValues();
 
-                return $configItem !== null;
-            },
-            ARRAY_FILTER_USE_BOTH
-        );
+        $channel['config'] = json_encode($this->filterConfig($channel['config']));
+        $storedValues['config'] = json_encode($this->filterConfig($storedValues['config']));
+
+        if (! empty(array_diff_assoc($channel, $storedValues))) {
+            $channel['changed_at'] = time() * 1000;
 
-        $channel['config'] = json_encode($config);
-        if ($this->channelId === null) {
-            $this->db->insert('channel', $channel);
-        } else {
             $this->db->update('channel', $channel, ['id = ?' => $this->channelId]);
         }
+
+        $this->db->commitTransaction();
+    }
+
+    /**
+     * Remove the channel
+     */
+    public function removeChannel(): void
+    {
+        $this->db->update(
+            'channel',
+            ['changed_at' => time() * 1000, 'deleted' => 'y'],
+            ['id = ?' => $this->channelId]
+        );
+    }
+
+    /**
+     * Get the channel name
+     *
+     * @return string
+     */
+    public function getChannelName(): string
+    {
+        return $this->getValue('name');
     }
 
     /**
@@ -332,4 +387,51 @@ protected function fromCurrentLocale(array $localeMap): ?string
 
         return $localeMap[$locale] ?? $localeMap[$default] ?? null;
     }
+
+    /**
+     * Filter the config array
+     *
+     * @param array $config
+     *
+     * @return ChannelOptionConfig
+     */
+    private function filterConfig(array $config): array
+    {
+        return array_filter(
+            $config,
+            function ($configItem, $key) {
+                if (isset($this->defaultChannelOptions[$key])) {
+                    return $this->defaultChannelOptions[$key] !== $configItem;
+                }
+
+                return $configItem !== null;
+            },
+            ARRAY_FILTER_USE_BOTH
+        );
+    }
+
+    /**
+     * Fetch the values from the database
+     *
+     * @return array
+     *
+     * @throws HttpNotFoundException
+     */
+    private function fetchDbValues(): array
+    {
+        /** @var Channel $channel */
+        $channel = Channel::on($this->db)
+            ->filter(Filter::equal('id', $this->channelId))
+            ->first();
+
+        if ($channel === null) {
+            throw new HttpNotFoundException($this->translate('Channel not found'));
+        }
+
+        return [
+            'name'      => $channel->name,
+            'type'      => $channel->type,
+            'config'    => json_decode($channel->config, true) ?? []
+        ];
+    }
 }
diff --git a/application/forms/ContactGroupForm.php b/application/forms/ContactGroupForm.php
index 575dfba3..d7d63ed8 100644
--- a/application/forms/ContactGroupForm.php
+++ b/application/forms/ContactGroupForm.php
@@ -8,10 +8,15 @@
 use Icinga\Module\Notifications\Common\Links;
 use Icinga\Module\Notifications\Model\Contact;
 use Icinga\Module\Notifications\Model\Contactgroup;
+use Icinga\Module\Notifications\Model\Rotation;
+use Icinga\Module\Notifications\Model\RotationMember;
+use Icinga\Module\Notifications\Model\RuleEscalation;
+use Icinga\Module\Notifications\Model\RuleEscalationRecipient;
 use Icinga\Web\Session;
 use ipl\Html\FormElement\SubmitElement;
 use ipl\Html\HtmlDocument;
 use ipl\Sql\Connection;
+use ipl\Sql\Select;
 use ipl\Stdlib\Filter;
 use ipl\Web\Common\CsrfCounterMeasure;
 use ipl\Web\Compat\CompatForm;
@@ -173,7 +178,8 @@ public function addGroup(): int
 
         $this->db->beginTransaction();
 
-        $this->db->insert('contactgroup', ['name' => trim($data['group_name'])]);
+        $changedAt = time() * 1000;
+        $this->db->insert('contactgroup', ['name' => trim($data['group_name']), 'changed_at' => $changedAt]);
 
         $groupIdentifier = $this->db->lastInsertId();
 
@@ -186,8 +192,9 @@ public function addGroup(): int
             $this->db->insert(
                 'contactgroup_member',
                 [
-                    'contactgroup_id' => $groupIdentifier,
-                    'contact_id'      => $contactId
+                    'contactgroup_id'   => $groupIdentifier,
+                    'contact_id'        => $contactId,
+                    'changed_at'        => $changedAt
                 ]
             );
         }
@@ -200,25 +207,23 @@ public function addGroup(): int
     /**
      * Edit the contact group
      *
-     * @return bool False if no changes found, true otherwise
+     * @return void
      */
-    public function editGroup(): bool
+    public function editGroup(): void
     {
-        $isUpdated = false;
         $values = $this->getValues();
 
         $this->db->beginTransaction();
 
         $storedValues = $this->fetchDbValues();
 
+        $changedAt = time() * 1000;
         if ($values['group_name'] !== $storedValues['group_name']) {
             $this->db->update(
                 'contactgroup',
-                ['name' => $values['group_name']],
+                ['name' => $values['group_name'], 'changed_at' => $changedAt],
                 ['id = ?' => $this->contactgroupId]
             );
-
-            $isUpdated = true;
         }
 
         $storedContacts = [];
@@ -235,34 +240,54 @@ public function editGroup(): bool
         $toAdd = array_diff($newContacts, $storedContacts);
 
         if (! empty($toDelete)) {
-            $this->db->delete(
+            $this->db->update(
                 'contactgroup_member',
+                ['changed_at' => $changedAt, 'deleted' => 'y'],
                 [
-                    'contactgroup_id = ?' => $this->contactgroupId,
-                    'contact_id IN (?)'   => $toDelete
+                    'contactgroup_id = ?'   => $this->contactgroupId,
+                    'contact_id IN (?)'     => $toDelete,
+                    'deleted = ?'           => 'n'
                 ]
             );
-
-            $isUpdated = true;
         }
 
         if (! empty($toAdd)) {
+            $contactsMarkedAsDeleted = $this->db->fetchCol(
+                (new Select())
+                    ->from('contactgroup_member')
+                    ->columns(['contact_id'])
+                    ->where([
+                        'contactgroup_id = ?'   => $this->contactgroupId,
+                        'deleted = ?'           => 'y',
+                        'contact_id IN (?)'     => $toAdd
+                    ])
+            );
+
+            $toAdd = array_diff($toAdd, $contactsMarkedAsDeleted);
             foreach ($toAdd as $contactId) {
                 $this->db->insert(
                     'contactgroup_member',
                     [
-                        'contactgroup_id' => $this->contactgroupId,
-                        'contact_id'      => $contactId
+                        'contactgroup_id'   => $this->contactgroupId,
+                        'contact_id'        => $contactId,
+                        'changed_at'        => $changedAt
                     ]
                 );
             }
 
-            $isUpdated = true;
+            if (! empty($contactsMarkedAsDeleted)) {
+                $this->db->update(
+                    'contactgroup_member',
+                    ['changed_at' => $changedAt, 'deleted' => 'n'],
+                    [
+                        'contactgroup_id = ?'   => $this->contactgroupId,
+                        'contact_id IN (?)'     => $contactsMarkedAsDeleted
+                    ]
+                );
+            }
         }
 
         $this->db->commitTransaction();
-
-        return $isUpdated;
     }
 
     /**
@@ -272,8 +297,90 @@ public function removeContactgroup(): void
     {
         $this->db->beginTransaction();
 
-        $this->db->delete('contactgroup_member', ['contactgroup_id = ?' => $this->contactgroupId]);
-        $this->db->delete('contactgroup', ['id = ?' => $this->contactgroupId]);
+        $markAsDeleted = ['changed_at' => time() * 1000, 'deleted' => 'y'];
+        $updateCondition = ['contactgroup_id = ?' => $this->contactgroupId, 'deleted = ?' => 'n'];
+
+        $rotationAndMemberIds = $this->db->fetchPairs(
+            RotationMember::on($this->db)
+                ->columns(['id', 'rotation_id'])
+                ->filter(Filter::equal('contactgroup_id', $this->contactgroupId))
+                ->assembleSelect()
+        );
+
+        $rotationMemberIds = array_keys($rotationAndMemberIds);
+        $rotationIds = array_values($rotationAndMemberIds);
+
+        $this->db->update('rotation_member', $markAsDeleted + ['position' => null], $updateCondition);
+
+        if (! empty($rotationMemberIds)) {
+            $this->db->update(
+                'timeperiod_entry',
+                $markAsDeleted,
+                ['rotation_member_id IN (?)' => $rotationMemberIds, 'deleted = ?' => 'n']
+            );
+        }
+
+        if (! empty($rotationIds)) {
+            $rotationIdsWithOtherMembers = $this->db->fetchCol(
+                RotationMember::on($this->db)
+                    ->columns('rotation_id')
+                    ->filter(Filter::all(
+                        Filter::equal('rotation_id', $rotationIds),
+                        Filter::unequal('contactgroup_id', $this->contactgroupId)
+                    ))->assembleSelect()
+            );
+
+            $toRemoveRotations = array_diff($rotationIds, $rotationIdsWithOtherMembers);
+
+            if (! empty($toRemoveRotations)) {
+                $rotations = Rotation::on($this->db)
+                    ->columns(['id', 'schedule_id', 'priority', 'timeperiod.id'])
+                    ->filter(Filter::equal('id', $toRemoveRotations));
+
+                /** @var Rotation $rotation */
+                foreach ($rotations as $rotation) {
+                    $rotation->delete();
+                }
+            }
+        }
+
+        $escalationIds = $this->db->fetchCol(
+            RuleEscalationRecipient::on($this->db)
+            ->columns('rule_escalation_id')
+            ->filter(Filter::equal('contactgroup_id', $this->contactgroupId))
+            ->assembleSelect()
+        );
+
+        $this->db->update('rule_escalation_recipient', $markAsDeleted, $updateCondition);
+
+        if (! empty($escalationIds)) {
+            $escalationIdsWithOtherRecipients = $this->db->fetchCol(
+                RuleEscalationRecipient::on($this->db)
+                    ->columns('rule_escalation_id')
+                    ->filter(Filter::all(
+                        Filter::equal('rule_escalation_id', $escalationIds),
+                        Filter::unequal('contactgroup_id', $this->contactgroupId)
+                    ))->assembleSelect()
+            );
+
+            $toRemoveEscalations = array_diff($escalationIds, $escalationIdsWithOtherRecipients);
+
+            if (! empty($toRemoveEscalations)) {
+                $this->db->update(
+                    'rule_escalation',
+                    $markAsDeleted + ['position' => null],
+                    ['id IN (?)' => $toRemoveEscalations]
+                );
+            }
+        }
+
+        $this->db->update('contactgroup_member', $markAsDeleted, $updateCondition);
+
+        $this->db->update(
+            'contactgroup',
+            $markAsDeleted,
+            ['id = ?' => $this->contactgroupId, 'deleted = ?' => 'n']
+        );
 
         $this->db->commitTransaction();
     }
@@ -297,8 +404,8 @@ private function fetchDbValues(): array
         }
 
         $groupMembers = [];
-        foreach ($group->contact->columns('id') as $contact) {
-            $groupMembers[] = $contact->id;
+        foreach ($group->contactgroup_member as $contact) {
+            $groupMembers[] = $contact->contact_id;
         }
 
         return [
diff --git a/application/forms/EventRuleForm.php b/application/forms/EventRuleForm.php
index 9ce497ef..2890098e 100644
--- a/application/forms/EventRuleForm.php
+++ b/application/forms/EventRuleForm.php
@@ -27,15 +27,6 @@ protected function assemble()
             ]
         );
 
-        $this->addElement(
-            'checkbox',
-            'is_active',
-            [
-                'label'  => $this->translate('Event Rule is active'),
-                'value'  => 'y'
-            ]
-        );
-
         $this->addElement('submit', 'btn_submit', [
             'label' => $this->translate('Save')
         ]);
diff --git a/application/forms/MoveRotationForm.php b/application/forms/MoveRotationForm.php
index e79b224b..24b9ae73 100644
--- a/application/forms/MoveRotationForm.php
+++ b/application/forms/MoveRotationForm.php
@@ -100,8 +100,9 @@ protected function onSuccess()
 
         $this->scheduleId = $rotation->schedule_id;
 
+        $changedAt = time() * 1000;
         // Free up the current priority used by the rotation in question
-        $this->db->update('rotation', ['priority' => 9999], ['id = ?' => $rotationId]);
+        $this->db->update('rotation', ['priority' => null, 'deleted' => 'y'], ['id = ?' => $rotationId]);
 
         // Update the priorities of the rotations that are affected by the move
         if ($newPriority < $rotation->priority) {
@@ -119,7 +120,7 @@ protected function onSuccess()
             foreach ($affectedRotations as $rotation) {
                 $this->db->update(
                     'rotation',
-                    ['priority' => new Expression('priority + 1')],
+                    ['priority' => new Expression('priority + 1'), 'changed_at' => $changedAt],
                     ['id = ?' => $rotation->id]
                 );
             }
@@ -138,14 +139,18 @@ protected function onSuccess()
             foreach ($affectedRotations as $rotation) {
                 $this->db->update(
                     'rotation',
-                    ['priority' => new Expression('priority - 1')],
+                    ['priority' => new Expression('priority - 1'), 'changed_at' => $changedAt],
                     ['id = ?' => $rotation->id]
                 );
             }
         }
 
         // Now insert the rotation at the new priority
-        $this->db->update('rotation', ['priority' => $newPriority], ['id = ?' => $rotationId]);
+        $this->db->update(
+            'rotation',
+            ['priority' => $newPriority, 'changed_at' => $changedAt, 'deleted' => 'n'],
+            ['id = ?' => $rotationId]
+        );
 
         if ($transactionStarted) {
             $this->db->commitTransaction();
diff --git a/application/forms/RotationConfigForm.php b/application/forms/RotationConfigForm.php
index 5ef25954..8b1f2fb9 100644
--- a/application/forms/RotationConfigForm.php
+++ b/application/forms/RotationConfigForm.php
@@ -75,6 +75,9 @@ class RotationConfigForm extends CompatForm
     /** @var ?DateTime The first handoff of a newer version for this rotation */
     protected $nextHandoff;
 
+    /** @var int The rotation id */
+    protected $rotationId;
+
     /**
      * Set the label for the submit button
      *
@@ -199,24 +202,7 @@ public function __construct(int $scheduleId, Connection $db)
      */
     public function loadRotation(int $rotationId): self
     {
-        /** @var ?Rotation $rotation */
-        $rotation = Rotation::on($this->db)
-            ->filter(Filter::equal('id', $rotationId))
-            ->first();
-        if ($rotation === null) {
-            throw new HttpNotFoundException($this->translate('Rotation not found'));
-        }
-
-        $formData = [
-            'mode' => $rotation->mode,
-            'name' => $rotation->name,
-            'priority' => $rotation->priority,
-            'schedule' => $rotation->schedule_id,
-            'options' => $rotation->options
-        ];
-        if (! self::EXPERIMENTAL_OVERRIDES) {
-            $formData['first_handoff'] = $rotation->first_handoff;
-        }
+        $this->rotationId = $rotationId;
 
         if (self::EXPERIMENTAL_OVERRIDES) {
             $getHandoff = function (Rotation $rotation): DateTime {
@@ -245,6 +231,14 @@ public function loadRotation(int $rotationId): self
                 return $handoff;
             };
 
+            /** @var ?Rotation $rotation */
+            $rotation = Rotation::on($this->db)
+                ->filter(Filter::equal('id', $this->rotationId))
+                ->first();
+            if ($rotation === null) {
+                throw new HttpNotFoundException($this->translate('Rotation not found'));
+            }
+
             $this->previousHandoff = $getHandoff($rotation);
 
             /** @var ?TimeperiodEntry $previousShift */
@@ -278,18 +272,7 @@ public function loadRotation(int $rotationId): self
             }
         }
 
-        $members = [];
-        foreach ($rotation->member->orderBy('position', SORT_ASC) as $member) {
-            if ($member->contact_id !== null) {
-                $members[] = 'contact:' . $member->contact_id;
-            } else {
-                $members[] = 'group:' . $member->contactgroup_id;
-            }
-        }
-
-        $formData['members'] = implode(',', $members);
-
-        $this->populate($formData);
+        $this->populate($this->fetchDbValues());
 
         return $this;
     }
@@ -327,10 +310,12 @@ private function createRotation(int $priority): Generator
             $data['actual_handoff'] = $firstHandoff->format('U.u') * 1000.0;
         }
 
+        $changedAt = time() * 1000;
+        $data['changed_at'] = $changedAt;
         $this->db->insert('rotation', $data);
         $rotationId = $this->db->lastInsertId();
 
-        $this->db->insert('timeperiod', ['owned_by_rotation_id' => $rotationId]);
+        $this->db->insert('timeperiod', ['owned_by_rotation_id' => $rotationId, 'changed_at' => $changedAt]);
         $timeperiodId = $this->db->lastInsertId();
 
         $knownMembers = [];
@@ -347,13 +332,15 @@ private function createRotation(int $priority): Generator
                     $this->db->insert('rotation_member', [
                         'rotation_id' => $rotationId,
                         'contact_id' => $id,
-                        'position' => $position
+                        'position' => $position,
+                        'changed_at' => $changedAt
                     ]);
                 } elseif ($type === 'group') {
                     $this->db->insert('rotation_member', [
                         'rotation_id' => $rotationId,
                         'contactgroup_id' => $id,
-                        'position' => $position
+                        'position' => $position,
+                        'changed_at' => $changedAt
                     ]);
                 }
 
@@ -377,6 +364,7 @@ private function createRotation(int $priority): Generator
                 'until_time' => $untilTime,
                 'timezone' => $rrule->getStartDate()->getTimezone()->getName(),
                 'rrule' => $rrule->getString(Rule::TZ_FIXED),
+                'changed_at' => $changedAt
             ]);
         }
     }
@@ -424,17 +412,24 @@ public function editRotation(int $rotationId): void
             $transactionStarted = $this->db->beginTransaction();
         }
 
+        if (! $this->hasChanges()) {
+            return;
+        }
+
         // Delay the creation, avoids intermediate constraint failures
         $createStmt = $this->createRotation((int) $priority);
 
         $allEntriesRemoved = true;
+        $changedAt = time() * 1000;
+        $markAsDeleted = ['changed_at' => $changedAt, 'deleted' => 'y'];
         if (self::EXPERIMENTAL_OVERRIDES) {
             // We only show a single name, even in case of multiple versions of a rotation.
             // To avoid confusion, we update all versions upon change of the name
-            $this->db->update('rotation', ['name' => $this->getValue('name')], [
-                'schedule_id = ?' => $this->scheduleId,
-                'priority = ?' => $priority
-            ]);
+            $this->db->update(
+                'rotation',
+                ['name' => $this->getValue('name'), 'changed_at' => $changedAt],
+                ['schedule_id = ?' => $this->scheduleId, 'priority = ?' => $priority]
+            );
 
             $firstHandoff = $createStmt->current();
             $timeperiodEntries = TimeperiodEntry::on($this->db)
@@ -458,7 +453,8 @@ public function editRotation(int $rotationId): void
                         'start_time' => $gapStart->format('U.u') * 1000.0,
                         'end_time' => $gapEnd->format('U.u') * 1000.0,
                         'until_time' => $gapEnd->format('U.u') * 1000.0,
-                        'timezone' => $gapStart->getTimezone()->getName()
+                        'timezone' => $gapStart->getTimezone()->getName(),
+                        'changed_at' => $changedAt
                     ]);
                 }
 
@@ -469,28 +465,44 @@ public function editRotation(int $rotationId): void
 
                 if ($lastHandoff === null) {
                     // If the handoff didn't happen at all, the entry can safely be removed
-                    $this->db->delete('timeperiod_entry', ['id = ?' => $timeperiodEntry->id]);
+                    $this->db->update('timeperiod_entry', $markAsDeleted, ['id = ?' => $timeperiodEntry->id]);
                 } else {
                     $allEntriesRemoved = false;
                     $this->db->update('timeperiod_entry', [
-                        'until_time' => $lastShiftEnd->format('U.u') * 1000.0,
-                        'rrule' => $rrule->setUntil($lastHandoff)->getString(Rule::TZ_FIXED)
+                        'until_time'    => $lastShiftEnd->format('U.u') * 1000.0,
+                        'rrule'         => $rrule->setUntil($lastHandoff)->getString(Rule::TZ_FIXED),
+                        'changed_at'    => $changedAt
                     ], ['id = ?' => $timeperiodEntry->id]);
                 }
             }
         } else {
-            $this->db->delete('timeperiod_entry', [
-                'timeperiod_id = ?' => (new Select())
-                    ->from('timeperiod')
-                    ->columns('id')
-                    ->where(['owned_by_rotation_id = ?' => $rotationId])
-            ]);
+            $this->db->update(
+                'timeperiod_entry',
+                $markAsDeleted,
+                [
+                    'deleted = ?'       => 'n',
+                    'timeperiod_id = ?' => (new Select())
+                        ->from('timeperiod')
+                        ->columns('id')
+                        ->where(['owned_by_rotation_id = ?' => $rotationId])
+                ]
+            );
         }
 
         if ($allEntriesRemoved) {
-            $this->db->delete('timeperiod', ['owned_by_rotation_id = ?' => $rotationId]);
-            $this->db->delete('rotation_member', ['rotation_id = ?' => $rotationId]);
-            $this->db->delete('rotation', ['id = ?' => $rotationId]);
+            $this->db->update('timeperiod', $markAsDeleted, ['owned_by_rotation_id = ?' => $rotationId]);
+
+            $this->db->update(
+                'rotation_member',
+                $markAsDeleted + ['position' => null],
+                ['rotation_id = ?' => $rotationId, 'deleted = ?' => 'n']
+            );
+
+            $this->db->update(
+                'rotation',
+                $markAsDeleted + ['priority' => null, 'first_handoff' => null],
+                ['id = ?' => $rotationId]
+            );
         }
 
         // Once constraint failures are impossible, create the new version
@@ -520,40 +532,13 @@ public function removeRotation(int $id): void
             $transactionStarted = $this->db->beginTransaction();
         }
 
-        $timeperiodId = $this->db->fetchScalar(
-            (new Select())
-                ->from('timeperiod')
-                ->columns('id')
-                ->where(['owned_by_rotation_id = ?' => $id])
-        );
-
-        $this->db->delete('timeperiod_entry', ['timeperiod_id = ?' => $timeperiodId]);
-        $this->db->delete('timeperiod', ['id = ?' => $timeperiodId]);
-        $this->db->delete('rotation_member', ['rotation_id = ?' => $id]);
-        $this->db->delete('rotation', ['id = ?' => $id]);
+        /** @var Rotation $rotation */
+        $rotation = Rotation::on($this->db)
+            ->columns(['id', 'schedule_id', 'priority', 'timeperiod.id'])
+            ->filter(Filter::equal('id', $id))
+            ->first();
 
-        $rotations = Rotation::on($this->db)
-            ->filter(Filter::equal('schedule_id', $this->scheduleId))
-            ->filter(Filter::equal('priority', $priority));
-        if ($rotations->count() === 0) {
-            $affectedRotations = $this->db->select(
-                (new Select())
-                    ->columns('id')
-                    ->from('rotation')
-                    ->where([
-                        'schedule_id = ?' => $this->scheduleId,
-                        'priority > ?' => $priority
-                    ])
-                    ->orderBy('priority ASC')
-            );
-            foreach ($affectedRotations as $rotation) {
-                $this->db->update(
-                    'rotation',
-                    ['priority' => new Expression('priority - 1')],
-                    ['id = ?' => $rotation->id]
-                );
-            }
-        }
+        $rotation->delete();
 
         if ($transactionStarted) {
             $this->db->commitTransaction();
@@ -578,39 +563,13 @@ public function wipeRotation(int $priority = null): void
         }
 
         $rotations = Rotation::on($this->db)
-            ->columns('id')
+            ->columns(['id', 'schedule_id', 'priority', 'timeperiod.id'])
             ->filter(Filter::equal('schedule_id', $this->scheduleId))
             ->filter(Filter::equal('priority', $priority));
-        foreach ($rotations as $rotation) {
-            $timeperiodId = $this->db->fetchScalar(
-                (new Select())
-                    ->from('timeperiod')
-                    ->columns('id')
-                    ->where(['owned_by_rotation_id = ?' => $rotation->id])
-            );
-
-            $this->db->delete('timeperiod_entry', ['timeperiod_id = ?' => $timeperiodId]);
-            $this->db->delete('timeperiod', ['id = ?' => $timeperiodId]);
-            $this->db->delete('rotation_member', ['rotation_id = ?' => $rotation->id]);
-            $this->db->delete('rotation', ['id = ?' => $rotation->id]);
-        }
 
-        $affectedRotations = $this->db->select(
-            (new Select())
-                ->columns('id')
-                ->from('rotation')
-                ->where([
-                    'schedule_id = ?' => $this->scheduleId,
-                    'priority > ?' => $priority
-                ])
-                ->orderBy('priority ASC')
-        );
-        foreach ($affectedRotations as $rotation) {
-            $this->db->update(
-                'rotation',
-                ['priority' => new Expression('priority - 1')],
-                ['id = ?' => $rotation->id]
-            );
+        /** @var Rotation $rotation */
+        foreach ($rotations as $rotation) {
+            $rotation->delete();
         }
 
         if ($transactionStarted) {
@@ -1543,4 +1502,70 @@ private function calculateRemainingHandoffs(Rule $rrule, DateInterval $shiftDura
 
         return $result;
     }
+
+    /**
+     * Fetch the values from the database
+     *
+     * @return array
+     *
+     * @throws HttpNotFoundException
+     */
+    private function fetchDbValues(): array
+    {
+        /** @var ?Rotation $rotation */
+        $rotation = Rotation::on($this->db)
+            ->filter(Filter::equal('id', $this->rotationId))
+            ->first();
+        if ($rotation === null) {
+            throw new HttpNotFoundException($this->translate('Rotation not found'));
+        }
+
+        $formData = [
+            'mode' => $rotation->mode,
+            'name' => $rotation->name,
+            'priority' => $rotation->priority,
+            'schedule' => $rotation->schedule_id,
+            'options' => $rotation->options
+        ];
+        if (! self::EXPERIMENTAL_OVERRIDES) {
+            $formData['first_handoff'] = $rotation->first_handoff;
+        }
+
+        $members = [];
+        foreach ($rotation->member->orderBy('position', SORT_ASC) as $member) {
+            if ($member->contact_id !== null) {
+                $members[] = 'contact:' . $member->contact_id;
+            } else {
+                $members[] = 'group:' . $member->contactgroup_id;
+            }
+        }
+
+        $formData['members'] = implode(',', $members);
+
+        return $formData;
+    }
+
+    /**
+     * Whether the form has changes
+     *
+     * @return bool
+     */
+    public function hasChanges(): bool
+    {
+        $values = $this->getValues();
+        $values['members'] = $this->getValue('members');
+
+        // only keys that are present in $values
+        $dbValuesToCompare = array_intersect_key($this->fetchDbValues(), $values);
+
+        $checker = static function ($a, $b) use (&$checker) {
+            if (! is_array($a) || ! is_array($b)) {
+                return $a <=> $b;
+            }
+
+            return empty(array_udiff_assoc($a, $b, $checker)) ? 0 : 1;
+        };
+
+        return ! empty(array_udiff_assoc($values, $dbValuesToCompare, $checker));
+    }
 }
diff --git a/application/forms/SaveEventRuleForm.php b/application/forms/SaveEventRuleForm.php
index f7bd7aa0..f19f25b1 100644
--- a/application/forms/SaveEventRuleForm.php
+++ b/application/forms/SaveEventRuleForm.php
@@ -5,7 +5,9 @@
 namespace Icinga\Module\Notifications\Forms;
 
 use Exception;
+use Icinga\Exception\Http\HttpNotFoundException;
 use Icinga\Module\Notifications\Common\Database;
+use Icinga\Module\Notifications\Model\Rule;
 use Icinga\Module\Notifications\Model\RuleEscalation;
 use Icinga\Module\Notifications\Model\RuleEscalationRecipient;
 use Icinga\Web\Notification;
@@ -44,8 +46,8 @@ class SaveEventRuleForm extends Form
     /** @var bool Whether to show a button to dismiss cached changes */
     protected $showDismissChangesButton = false;
 
-    /** @var bool Whether to disable the remove button */
-    protected $disableRemoveButton = false;
+    /** @var int The rule id */
+    protected $ruleId;
 
     /**
      * Create a new SaveEventRuleForm
@@ -78,20 +80,6 @@ public function setSubmitButtonDisabled(bool $state = true): self
         return $this;
     }
 
-    /**
-     * Set whether to enable or disable the remove button
-     *
-     * @param bool $state
-     *
-     * @return $this
-     */
-    public function setRemoveButtonDisabled(bool $state = true): self
-    {
-        $this->disableRemoveButton = $state;
-
-        return $this;
-    }
-
     /**
      * Set the submit label
      *
@@ -191,19 +179,6 @@ protected function assemble()
             ]);
             $this->registerElement($removeBtn);
 
-            $this->getElement('remove')
-                ->getAttributes()
-                ->registerAttributeCallback('disabled', function () {
-                    return $this->disableRemoveButton;
-                })
-                ->registerAttributeCallback('title', function () {
-                    if ($this->disableRemoveButton) {
-                        return $this->translate(
-                            'There exist active incidents for this event rule and hence cannot be deleted'
-                        );
-                    }
-                });
-
             $additionalButtons[] = $removeBtn;
         }
 
@@ -237,11 +212,12 @@ public function addRule(array $config): int
 
         $db->beginTransaction();
 
+        $changedAt = time() * 1000;
         $db->insert('rule', [
             'name' => $config['name'],
             'timeperiod_id' => $config['timeperiod_id'] ?? null,
             'object_filter' => $config['object_filter'] ?? null,
-            'is_active' => $config['is_active'] ?? 'n'
+            'changed_at'    => $changedAt
         ]);
         $ruleId = $db->lastInsertId();
 
@@ -251,14 +227,16 @@ public function addRule(array $config): int
                 'position' => $position,
                 'condition' => $escalationConfig['condition'] ?? null,
                 'name' => $escalationConfig['name'] ?? null,
-                'fallback_for' => $escalationConfig['fallback_for'] ?? null
+                'fallback_for' => $escalationConfig['fallback_for'] ?? null,
+                'changed_at' => $changedAt
             ]);
             $escalationId = $db->lastInsertId();
 
             foreach ($escalationConfig['recipient'] ?? [] as $recipientConfig) {
                 $data = [
                     'rule_escalation_id' => $escalationId,
-                    'channel_id' => $recipientConfig['channel_id']
+                    'channel_id' => $recipientConfig['channel_id'],
+                    'changed_at' => $changedAt
                 ];
 
                 switch (true) {
@@ -294,6 +272,7 @@ public function addRule(array $config): int
      */
     private function insertOrUpdateEscalations($ruleId, array $escalations, Connection $db, bool $insert = false): void
     {
+        $changedAt = time() * 1000;
         foreach ($escalations as $position => $escalationConfig) {
             if ($insert) {
                 $db->insert('rule_escalation', [
@@ -301,18 +280,19 @@ private function insertOrUpdateEscalations($ruleId, array $escalations, Connecti
                     'position' => $position,
                     'condition' => $escalationConfig['condition'] ?? null,
                     'name' => $escalationConfig['name'] ?? null,
-                    'fallback_for' => $escalationConfig['fallback_for'] ?? null
+                    'fallback_for' => $escalationConfig['fallback_for'] ?? null,
+                    'changed_at' => $changedAt
                 ]);
 
                 $escalationId = $db->lastInsertId();
             } else {
                 $escalationId = $escalationConfig['id'];
-
                 $db->update('rule_escalation', [
                     'position' => $position,
                     'condition' => $escalationConfig['condition'] ?? null,
                     'name' => $escalationConfig['name'] ?? null,
-                    'fallback_for' => $escalationConfig['fallback_for'] ?? null
+                    'fallback_for' => $escalationConfig['fallback_for'] ?? null,
+                    'changed_at' => $changedAt
                 ], ['id = ?' => $escalationId, 'rule_id = ?' => $ruleId]);
                 $recipientsToRemove = [];
 
@@ -336,14 +316,19 @@ function (array $element) use ($recipientId) {
                 }
 
                 if (! empty($recipientsToRemove)) {
-                    $db->delete('rule_escalation_recipient', ['id IN (?)' => $recipientsToRemove]);
+                    $db->update(
+                        'rule_escalation_recipient',
+                        ['changed_at' => $changedAt, 'deleted' => 'y'],
+                        ['id IN (?)' => $recipientsToRemove, 'deleted = ?' => 'n']
+                    );
                 }
             }
 
             foreach ($escalationConfig['recipient'] ?? [] as $recipientConfig) {
                 $data = [
                     'rule_escalation_id' => $escalationId,
-                    'channel_id' => $recipientConfig['channel_id']
+                    'channel_id' => $recipientConfig['channel_id'],
+                    'changed_at' => $changedAt
                 ];
 
                 switch (true) {
@@ -367,7 +352,11 @@ function (array $element) use ($recipientId) {
                 if (! isset($recipientConfig['id'])) {
                     $db->insert('rule_escalation_recipient', $data);
                 } else {
-                    $db->update('rule_escalation_recipient', $data, ['id = ?' => $recipientConfig['id']]);
+                    $db->update(
+                        'rule_escalation_recipient',
+                        $data + ['changed_at' => $changedAt],
+                        ['id = ?' => $recipientConfig['id']]
+                    );
                 }
             }
         }
@@ -383,27 +372,42 @@ function (array $element) use ($recipientId) {
      */
     public function editRule(int $id, array $config): void
     {
+        $this->ruleId = $id;
+
         $db = Database::get();
 
         $db->beginTransaction();
 
-        $db->update('rule', [
-            'name' => $config['name'],
-            'timeperiod_id' => $config['timeperiod_id'] ?? null,
-            'object_filter' => $config['object_filter'] ?? null,
-            'is_active' => $config['is_active'] ?? 'n'
-        ], ['id = ?' => $id]);
+        $storedValues = $this->fetchDbValues();
+
+        $values = $this->getChanges($storedValues, $config);
+
+        $data = array_filter([
+            'name'      => $values['name'] ?? null
+        ]);
+
+        if (array_key_exists('object_filter', $values)) {
+            $data['object_filter'] = $values['object_filter'];
+        }
+
+        $changedAt = time() * 1000;
+        if (! empty($data)) {
+            $db->update('rule', $data + ['changed_at' => $changedAt], ['id = ?' => $id]);
+        }
 
-        $escalationsFromDb = RuleEscalation::on($db)
-            ->filter(Filter::equal('rule_id', $id));
+        if (! isset($values['rule_escalation'])) {
+            $db->commitTransaction();
+
+            return;
+        }
 
         $escalationsInCache = $config['rule_escalation'];
 
         $escalationsToUpdate = [];
         $escalationsToRemove = [];
 
-        foreach ($escalationsFromDb as $escalationInDB) {
-            $escalationId = $escalationInDB->id;
+        foreach ($storedValues['rule_escalation'] as $escalationInDB) {
+            $escalationId = $escalationInDB['id'];
             $escalationInCache = array_filter($escalationsInCache, function (array $element) use ($escalationId) {
                 return (int) $element['id'] === $escalationId;
             });
@@ -422,9 +426,19 @@ public function editRule(int $id, array $config): void
         // Escalations to add
         $escalationsToAdd = $escalationsInCache;
 
+        $markAsDeleted = ['changed_at' => $changedAt, 'deleted' => 'y'];
         if (! empty($escalationsToRemove)) {
-            $db->delete('rule_escalation_recipient', ['rule_escalation_id IN (?)' => $escalationsToRemove]);
-            $db->delete('rule_escalation', ['id IN (?)' => $escalationsToRemove]);
+            $db->update(
+                'rule_escalation_recipient',
+                $markAsDeleted,
+                ['rule_escalation_id IN (?)' => $escalationsToRemove, 'deleted = ?' => 'n']
+            );
+
+            $db->update(
+                'rule_escalation',
+                $markAsDeleted + ['position' => null],
+                ['id IN (?)' => $escalationsToRemove]
+            );
         }
 
         if (! empty($escalationsToAdd)) {
@@ -451,21 +465,24 @@ public function removeRule(int $id): void
 
         $db->beginTransaction();
 
-        $escalations = RuleEscalation::on($db)
-            ->columns('id')
-            ->filter(Filter::equal('rule_id', $id));
-
-        $escalationsToRemove = [];
-        foreach ($escalations as $escalation) {
-            $escalationsToRemove[] = $escalation->id;
-        }
+        $escalationsToRemove = $db->fetchCol(
+            RuleEscalation::on($db)
+                ->columns('id')
+                ->filter(Filter::equal('rule_id', $id))
+                ->assembleSelect()
+        );
 
+        $markAsDeleted = ['changed_at' => time() * 1000, 'deleted' => 'y'];
         if (! empty($escalationsToRemove)) {
-            $db->delete('rule_escalation_recipient', ['rule_escalation_id IN (?)' => $escalationsToRemove]);
+            $db->update(
+                'rule_escalation_recipient',
+                $markAsDeleted,
+                ['rule_escalation_id IN (?)' => $escalationsToRemove, 'deleted = ?' => 'n']
+            );
         }
 
-        $db->delete('rule_escalation', ['rule_id = ?' => $id]);
-        $db->delete('rule', ['id = ?' => $id]);
+        $db->update('rule_escalation', $markAsDeleted + ['position' => null], ['rule_id = ?' => $id]);
+        $db->update('rule', $markAsDeleted, ['id = ?' => $id]);
 
         $db->commitTransaction();
     }
@@ -478,4 +495,85 @@ protected function onError()
             }
         }
     }
+
+    /**
+     * Fetch the values from the database
+     *
+     * @return array
+     *
+     * @throws HttpNotFoundException
+     */
+    private function fetchDbValues(): array
+    {
+        $query = Rule::on(Database::get())
+            ->columns(['id', 'name', 'object_filter'])
+            ->filter(Filter::equal('id', $this->ruleId));
+
+        $rule = $query->first();
+        if ($rule === null) {
+            throw new HttpNotFoundException($this->translate('Rule not found'));
+        }
+
+        $config = iterator_to_array($rule);
+
+        $ruleEscalations = $rule
+            ->rule_escalation
+            ->withoutColumns(['changed_at', 'deleted']);
+
+        foreach ($ruleEscalations as $re) {
+            foreach ($re as $k => $v) {
+                $config[$re->getTableName()][$re->position][$k] = $v;
+            }
+
+            $escalationRecipients = $re
+                ->rule_escalation_recipient
+                ->withoutColumns(['changed_at', 'deleted']);
+
+            foreach ($escalationRecipients as $recipient) {
+                $config[$re->getTableName()][$re->position]['recipient'][] = iterator_to_array($recipient);
+            }
+        }
+
+        if (! isset($config['rule_escalation'])) {
+            $config['rule_escalation'] = [];
+        }
+
+        $config['showSearchbar'] = ! empty($config['object_filter']);
+
+        return $config;
+    }
+
+    /**
+     * Get the newly made changes
+     *
+     * @return array
+     */
+    public function getChanges(array $storedValues, array $formValues): array
+    {
+        unset($formValues['conditionPlusButtonPosition']);
+        $dbValuesToCompare = array_intersect_key($storedValues, $formValues);
+
+        if (count($formValues, COUNT_RECURSIVE) < count($dbValuesToCompare, COUNT_RECURSIVE)) {
+            // fewer values in the form than in the db, escalation(s) has been removed
+            if ($formValues['name'] === $dbValuesToCompare['name']) {
+                unset($formValues['name']);
+            }
+
+            if ($formValues['object_filter'] === $dbValuesToCompare['object_filter']) {
+                unset($formValues['object_filter']);
+            }
+
+            return $formValues;
+        }
+
+        $checker = static function ($a, $b) use (&$checker) {
+            if (! is_array($a) || ! is_array($b)) {
+                return $a <=> $b;
+            }
+
+            return empty(array_udiff_assoc($a, $b, $checker)) ? 0 : 1;
+        };
+
+        return array_udiff_assoc($formValues, $dbValuesToCompare, $checker);
+    }
 }
diff --git a/application/forms/ScheduleForm.php b/application/forms/ScheduleForm.php
index d74e0d01..5d9b1f4b 100644
--- a/application/forms/ScheduleForm.php
+++ b/application/forms/ScheduleForm.php
@@ -5,12 +5,12 @@
 namespace Icinga\Module\Notifications\Forms;
 
 use Icinga\Exception\Http\HttpNotFoundException;
-use Icinga\Module\Notifications\Common\Database;
 use Icinga\Module\Notifications\Model\Rotation;
+use Icinga\Module\Notifications\Model\RuleEscalationRecipient;
 use Icinga\Module\Notifications\Model\Schedule;
-use Icinga\Module\Notifications\Model\Timeperiod;
 use Icinga\Web\Session;
 use ipl\Html\HtmlDocument;
+use ipl\Sql\Connection;
 use ipl\Stdlib\Filter;
 use ipl\Web\Common\CsrfCounterMeasure;
 use ipl\Web\Compat\CompatForm;
@@ -25,6 +25,17 @@ class ScheduleForm extends CompatForm
     /** @var bool */
     protected $showRemoveButton = false;
 
+    /** @var Connection */
+    private $db;
+
+    /** @var ?int */
+    private $scheduleId;
+
+    public function __construct(Connection $db)
+    {
+        $this->db = $db;
+    }
+
     public function setSubmitLabel(string $label): self
     {
         $this->submitLabel = $label;
@@ -54,57 +65,88 @@ public function hasBeenRemoved(): bool
 
     public function loadSchedule(int $id): void
     {
-        $db = Database::get();
-
-        $schedule = Schedule::on($db)
-            ->filter(Filter::equal('id', $id))
-            ->first();
-        if ($schedule === null) {
-            throw new HttpNotFoundException($this->translate('Schedule not found'));
-        }
-
-        $this->populate(['name' => $schedule->name]);
+        $this->scheduleId = $id;
+        $this->populate($this->fetchDbValues());
     }
 
     public function addSchedule(): int
     {
-        $db = Database::get();
-
-        $db->insert('schedule', [
-            'name' => $this->getValue('name')
+        $this->db->insert('schedule', [
+            'name' => $this->getValue('name'),
+            'changed_at' => time() * 1000
         ]);
 
-        return $db->lastInsertId();
+        return $this->db->lastInsertId();
     }
 
     public function editSchedule(int $id): void
     {
-        $db = Database::get();
+        $this->db->beginTransaction();
+
+        $values = $this->getValues();
+        $storedValues = $this->fetchDbValues();
+
+        if ($values === $storedValues) {
+            return;
+        }
 
-        $db->update('schedule', [
-            'name' => $this->getValue('name')
+        $this->db->update('schedule', [
+            'name'          => $values['name'],
+            'changed_at'    => time() * 1000
         ], ['id = ?' => $id]);
+
+        $this->db->commitTransaction();
     }
 
     public function removeSchedule(int $id): void
     {
-        $db = Database::get();
-        $db->beginTransaction();
+        $this->db->beginTransaction();
 
-        $rotations = Rotation::on($db)
-            ->columns('priority')
+        $rotations = Rotation::on($this->db)
+            ->columns(['id', 'schedule_id', 'priority', 'timeperiod.id'])
             ->filter(Filter::equal('schedule_id', $id))
             ->orderBy('priority', SORT_DESC);
 
-        $rotationConfigForm = new RotationConfigForm($id, $db);
-
+        /** @var Rotation $rotation */
         foreach ($rotations as $rotation) {
-            $rotationConfigForm->wipeRotation($rotation->priority);
+            $rotation->delete();
         }
 
-        $db->delete('schedule', ['id = ?' => $id]);
+        $markAsDeleted = ['changed_at' => time() * 1000, 'deleted' => 'y'];
+
+        $escalationIds = $this->db->fetchCol(
+            RuleEscalationRecipient::on($this->db)
+                ->columns('rule_escalation_id')
+                ->filter(Filter::equal('schedule_id', $id))
+                ->assembleSelect()
+        );
+
+        $this->db->update('rule_escalation_recipient', $markAsDeleted, ['schedule_id = ?' => $id]);
+
+        if (! empty($escalationIds)) {
+            $escalationIdsWithOtherRecipients = $this->db->fetchCol(
+                RuleEscalationRecipient::on($this->db)
+                    ->columns('rule_escalation_id')
+                    ->filter(Filter::all(
+                        Filter::equal('rule_escalation_id', $escalationIds),
+                        Filter::unequal('schedule_id', $id)
+                    ))->assembleSelect()
+            );
+
+            $toRemoveEscalations = array_diff($escalationIds, $escalationIdsWithOtherRecipients);
+
+            if (! empty($toRemoveEscalations)) {
+                $this->db->update(
+                    'rule_escalation',
+                    $markAsDeleted + ['position' => null],
+                    ['id IN (?)' => $toRemoveEscalations]
+                );
+            }
+        }
 
-        $db->commitTransaction();
+        $this->db->update('schedule', $markAsDeleted, ['id = ?' => $id]);
+
+        $this->db->commitTransaction();
     }
 
     protected function assemble()
@@ -131,4 +173,26 @@ protected function assemble()
 
         $this->addElement($this->createCsrfCounterMeasure(Session::getSession()->getId()));
     }
+
+    /**
+     * Fetch the values from the database
+     *
+     * @return string[]
+     *
+     * @throws HttpNotFoundException
+     */
+    private function fetchDbValues(): array
+    {
+        /** @var ?Schedule $schedule */
+        $schedule = Schedule::on($this->db)
+            ->columns('name')
+            ->filter(Filter::equal('id', $this->scheduleId))
+            ->first();
+
+        if ($schedule === null) {
+            throw new HttpNotFoundException($this->translate('Schedule not found'));
+        }
+
+        return ['name' => $schedule->name];
+    }
 }
diff --git a/application/forms/SourceForm.php b/application/forms/SourceForm.php
index d83f5564..ca8f9ee0 100644
--- a/application/forms/SourceForm.php
+++ b/application/forms/SourceForm.php
@@ -4,12 +4,14 @@
 
 namespace Icinga\Module\Notifications\Forms;
 
+use Icinga\Exception\Http\HttpNotFoundException;
 use Icinga\Module\Notifications\Model\Source;
 use Icinga\Web\Session;
 use ipl\Html\BaseHtmlElement;
 use ipl\Html\Contract\FormSubmitElement;
 use ipl\Html\FormElement\CheckboxElement;
 use ipl\Sql\Connection;
+use ipl\Stdlib\Filter;
 use ipl\Validator\CallbackValidator;
 use ipl\Validator\X509CertValidator;
 use ipl\Web\Common\CsrfCounterMeasure;
@@ -28,10 +30,9 @@ class SourceForm extends CompatForm
     /** @var ?int */
     private $sourceId;
 
-    public function __construct(Connection $db, ?int $sourceId = null)
+    public function __construct(Connection $db)
     {
         $this->db = $db;
-        $this->sourceId = $sourceId;
     }
 
     protected function assemble(): void
@@ -263,38 +264,56 @@ public function hasBeenSubmitted()
         return parent::hasBeenSubmitted();
     }
 
-    /** @param iterable<string, mixed>|Source $values */
-    public function populate($values)
+    /**
+     * Load the source with given id
+     *
+     * @param int $id
+     *
+     * @return $this
+     */
+    public function loadSource(int $id): self
     {
-        if ($values instanceof Source) {
-            $values = [
-                'name' => $values->name,
-                'type' => $values->type,
-                'icinga2_base_url' => $values->icinga2_base_url,
-                'icinga2_auth_user' => $values->icinga2_auth_user,
-                'icinga2_auth_pass' => $values->icinga2_auth_pass,
-                'icinga2_ca_pem' => $values->icinga2_ca_pem,
-                'icinga2_common_name' => $values->icinga2_common_name,
-                'icinga2_insecure_tls' => $values->icinga2_insecure_tls
-            ];
-        }
+        $this->sourceId = $id;
 
-        parent::populate($values);
+        $this->populate($this->fetchDbValues());
 
         return $this;
     }
 
-    protected function onSuccess(): void
+    /**
+     * Add the new source
+     */
+    public function addSource(): void
     {
-        $pressedButton = $this->getPressedSubmitElement();
-        if ($pressedButton && $pressedButton->getName() === 'delete') {
-            $this->db->delete('source', ['id = ?' => $this->sourceId]);
+        $source = $this->getValues();
 
-            return;
-        }
+        // Not using PASSWORD_DEFAULT, as the used algorithm should
+        // be kept in sync with what the daemon understands
+        $source['listener_password_hash'] = password_hash(
+            $this->getValue('listener_password'),
+            self::HASH_ALGORITHM
+        );
+
+        $source['changed_at'] = time() * 1000;
+
+        $this->db->insert('source', $source);
+    }
+
+    /**
+     * Edit the source
+     *
+     * @return void
+     */
+    public function editSource(): void
+    {
+        $this->db->beginTransaction();
 
         $source = $this->getValues();
 
+        if (empty(array_diff_assoc($source, $this->fetchDbValues()))) {
+            return;
+        }
+
         /** @var ?string $listenerPassword */
         $listenerPassword = $this->getValue('listener_password');
         if ($listenerPassword) {
@@ -303,10 +322,61 @@ protected function onSuccess(): void
             $source['listener_password_hash'] = password_hash($listenerPassword, self::HASH_ALGORITHM);
         }
 
-        if ($this->sourceId === null) {
-            $this->db->insert('source', $source);
-        } else {
-            $this->db->update('source', $source, ['id = ?' => $this->sourceId]);
+        $source['changed_at'] = time() * 1000;
+        $this->db->update('source', $source, ['id = ?' => $this->sourceId]);
+
+        $this->db->commitTransaction();
+    }
+
+    /**
+     * Remove the source
+     */
+    public function removeSource(): void
+    {
+        $this->db->update(
+            'source',
+            ['changed_at' => time() * 1000, 'deleted' => 'y'],
+            ['id = ?' => $this->sourceId]
+        );
+    }
+
+    /**
+     * Get the source name
+     *
+     * @return string
+     */
+    public function getSourceName(): string
+    {
+        return $this->getValue('name');
+    }
+
+    /**
+     * Fetch the values from the database
+     *
+     * @return array
+     *
+     * @throws HttpNotFoundException
+     */
+    private function fetchDbValues(): array
+    {
+        /** @var ?Source $source */
+        $source = Source::on($this->db)
+            ->filter(Filter::equal('id', $this->sourceId))
+            ->first();
+
+        if ($source === null) {
+            throw new HttpNotFoundException($this->translate('Source not found'));
         }
+
+        return [
+            'name'                  => $source->name,
+            'type'                  => $source->type,
+            'icinga2_base_url'      => $source->icinga2_base_url,
+            'icinga2_auth_user'     => $source->icinga2_auth_user,
+            'icinga2_auth_pass'     => $source->icinga2_auth_pass,
+            'icinga2_ca_pem'        => $source->icinga2_ca_pem,
+            'icinga2_common_name'   => $source->icinga2_common_name,
+            'icinga2_insecure_tls'  => $source->icinga2_insecure_tls
+        ];
     }
 }
diff --git a/library/Notifications/Common/Database.php b/library/Notifications/Common/Database.php
index a067d7a7..abfefa50 100644
--- a/library/Notifications/Common/Database.php
+++ b/library/Notifications/Common/Database.php
@@ -18,6 +18,28 @@
 
 final class Database
 {
+    /**
+     * @var string[] Tables with a deleted flag
+     *
+     * The filter `deleted=n` is automatically added to these tables.
+     */
+    private const TABLES_WITH_DELETED_FLAG = [
+        'channel',
+        'contact',
+        'contact_address',
+        'contactgroup',
+        'contactgroup_member',
+        'rotation',
+        'rotation_member',
+        'rule',
+        'rule_escalation',
+        'rule_escalation_recipient',
+        'schedule',
+        'source',
+        'timeperiod',
+        'timeperiod_entry',
+    ];
+
     /** @var Connection Database connection */
     private static $instance;
 
@@ -104,6 +126,30 @@ private static function getConnection(): Connection
                 });
         }
 
+        $db->getQueryBuilder()
+            ->on(QueryBuilder::ON_ASSEMBLE_SELECT, function (Select $select) {
+                $from = $select->getFrom();
+                $baseTableName = reset($from);
+
+                if (! in_array($baseTableName, self::TABLES_WITH_DELETED_FLAG, true)) {
+                    return;
+                }
+
+                $baseTableAlias = key($from);
+                if (! is_string($baseTableAlias)) {
+                    $baseTableAlias = $baseTableName;
+                }
+
+                $condition = 'deleted = ?';
+                $where = $select->getWhere();
+
+                if ($where && self::hasCondition($baseTableAlias, $condition, $where)) {
+                    return;
+                }
+
+                $select->where([$baseTableAlias . '.' . $condition => 'n']);
+            });
+
         return $db;
     }
 
@@ -144,4 +190,31 @@ public static function registerGroupBy(Query $query, Select $select): void
 
         $select->groupBy($groupBy);
     }
+
+    /**
+     * Check if the given condition is part of the where clause with value 'y'
+     *
+     * @param string $conditionToFind
+     * @param array<int|string, int|string> $where
+     *
+     * @return bool
+     */
+    private static function hasCondition(string $baseTable, string $conditionToFind, array $where): bool
+    {
+        foreach ($where as $condition => $value) {
+            if (is_array($value)) {
+                $found = self::hasCondition($baseTable, $conditionToFind, $value);
+            } else {
+                $found = (
+                    $condition === $conditionToFind || $condition === $baseTable . '.' . $conditionToFind
+                    ) && $value === 'y';
+            }
+
+            if ($found) {
+                return true;
+            }
+        }
+
+        return false;
+    }
 }
diff --git a/library/Notifications/Model/AvailableChannelType.php b/library/Notifications/Model/AvailableChannelType.php
index 84fa77df..0cec05cb 100644
--- a/library/Notifications/Model/AvailableChannelType.php
+++ b/library/Notifications/Model/AvailableChannelType.php
@@ -5,8 +5,18 @@
 namespace Icinga\Module\Notifications\Model;
 
 use ipl\Orm\Model;
+use ipl\Orm\Query;
 use ipl\Orm\Relations;
 
+/**
+ * @property string $type
+ * @property string $name
+ * @property string $version
+ * @property string $author
+ * @property string $config_attrs
+ *
+ * @property Query|Channel $channel
+ */
 class AvailableChannelType extends Model
 {
     public function getTableName(): string
@@ -14,7 +24,7 @@ public function getTableName(): string
         return 'available_channel_type';
     }
 
-    public function getKeyName()
+    public function getKeyName(): string
     {
         return 'type';
     }
@@ -24,7 +34,7 @@ public function getColumns(): array
         return [
             'name',
             'version',
-            'author_name',
+            'author',
             'config_attrs',
         ];
     }
diff --git a/library/Notifications/Model/Channel.php b/library/Notifications/Model/Channel.php
index e857e277..cc4f8103 100644
--- a/library/Notifications/Model/Channel.php
+++ b/library/Notifications/Model/Channel.php
@@ -4,11 +4,29 @@
 
 namespace Icinga\Module\Notifications\Model;
 
+use DateTime;
+use ipl\Orm\Behavior\BoolCast;
+use ipl\Orm\Behavior\MillisecondTimestamp;
+use ipl\Orm\Behaviors;
 use ipl\Orm\Model;
+use ipl\Orm\Query;
 use ipl\Orm\Relations;
 use ipl\Sql\Connection;
 use ipl\Web\Widget\Icon;
 
+/**
+ * @property int $id
+ * @property string $name
+ * @property string $type
+ * @property ?string $config
+ * @property DateTime $changed_at
+ * @property bool $deleted
+ *
+ * @property Query|IncidentHistory $incident_history
+ * @property Query|RuleEscalationRecipient $rule_escalation_recipient
+ * @property Query|Contact $contact
+ * @property Query|AvailableChannelType $available_channel_type
+ */
 class Channel extends Model
 {
     public function getTableName(): string
@@ -26,30 +44,39 @@ public function getColumns(): array
         return [
             'name',
             'type',
-            'config'
+            'config',
+            'changed_at',
+            'deleted'
         ];
     }
 
-    public function getColumnDefinitions()
+    public function getColumnDefinitions(): array
     {
         return [
-            'name'   => t('Name'),
-            'type'   => t('Type'),
+            'name'          => t('Name'),
+            'type'          => t('Type'),
+            'changed_at'    => t('Changed At')
         ];
     }
 
-    public function getSearchColumns()
+    public function getSearchColumns(): array
     {
         return ['name'];
     }
 
 
-    public function getDefaultSort()
+    public function getDefaultSort(): array
     {
         return ['name'];
     }
 
-    public function createRelations(Relations $relations)
+    public function createBehaviors(Behaviors $behaviors): void
+    {
+        $behaviors->add(new MillisecondTimestamp(['changed_at']));
+        $behaviors->add(new BoolCast(['deleted']));
+    }
+
+    public function createRelations(Relations $relations): void
     {
         $relations->hasMany('incident_history', IncidentHistory::class)->setJoinType('LEFT');
         $relations->hasMany('rule_escalation_recipient', RuleEscalationRecipient::class)->setJoinType('LEFT');
@@ -91,9 +118,9 @@ public function getIcon(): Icon
     public static function fetchChannelNames(Connection $conn): array
     {
         $channels = [];
+        $query = Channel::on($conn);
         /** @var Channel $channel */
-        foreach (Channel::on($conn) as $channel) {
-            /** @var string $name */
+        foreach ($query as $channel) {
             $name = $channel->name;
             $channels[$channel->id] = $name;
         }
diff --git a/library/Notifications/Model/Contact.php b/library/Notifications/Model/Contact.php
index 539e1728..10f17b01 100644
--- a/library/Notifications/Model/Contact.php
+++ b/library/Notifications/Model/Contact.php
@@ -4,13 +4,32 @@
 
 namespace Icinga\Module\Notifications\Model;
 
+use DateTime;
+use ipl\Orm\Behavior\BoolCast;
 use Icinga\Module\Notifications\Model\Behavior\HasAddress;
+use ipl\Orm\Behavior\MillisecondTimestamp;
 use ipl\Orm\Behaviors;
 use ipl\Orm\Model;
+use ipl\Orm\Query;
 use ipl\Orm\Relations;
 
 /**
  * @property int $id
+ * @property string $full_name
+ * @property ?string $username
+ * @property int $default_channel_id
+ * @property DateTime $changed_at
+ * @property bool $deleted
+ *
+ * @property Query|Channel $channel
+ * @property Query|Incident $incident
+ * @property Query|IncidentContact $incident_contact
+ * @property Query|IncidentHistory $incident_history
+ * @property Query|RotationMember $rotation_member
+ * @property Query|ContactAddress $contact_address
+ * @property Query|RuleEscalationRecipient $rule_escalation_recipient
+ * @property Query|ContactgroupMember $contactgroup_member
+ * @property Query|Contactgroup $contactgroup
  */
 class Contact extends Model
 {
@@ -29,34 +48,39 @@ public function getColumns(): array
         return [
             'full_name',
             'username',
-            'default_channel_id'
+            'default_channel_id',
+            'changed_at',
+            'deleted'
         ];
     }
 
-    public function getColumnDefinitions()
+    public function getColumnDefinitions(): array
     {
         return [
-            'full_name' => t('Full Name'),
-            'username'  => t('Username')
+            'full_name'     => t('Full Name'),
+            'username'      => t('Username'),
+            'changed_at'    => t('Changed At')
         ];
     }
 
-    public function getSearchColumns()
+    public function getSearchColumns(): array
     {
         return ['full_name'];
     }
 
-    public function createBehaviors(Behaviors $behaviors)
+    public function createBehaviors(Behaviors $behaviors): void
     {
         $behaviors->add(new HasAddress());
+        $behaviors->add(new MillisecondTimestamp(['changed_at']));
+        $behaviors->add(new BoolCast(['deleted']));
     }
 
-    public function getDefaultSort()
+    public function getDefaultSort(): array
     {
         return ['full_name'];
     }
 
-    public function createRelations(Relations $relations)
+    public function createRelations(Relations $relations): void
     {
         $relations->belongsTo('channel', Channel::class)
             ->setCandidateKey('default_channel_id');
@@ -73,6 +97,8 @@ public function createRelations(Relations $relations)
         $relations->hasMany('rule_escalation_recipient', RuleEscalationRecipient::class)
             ->setJoinType('LEFT');
 
+        $relations->hasMany('contactgroup_member', ContactgroupMember::class);
+
         $relations->belongsToMany('contactgroup', Contactgroup::class)
             ->through('contactgroup_member')
             ->setJoinType('LEFT');
diff --git a/library/Notifications/Model/ContactAddress.php b/library/Notifications/Model/ContactAddress.php
index 14ebd705..712a2afd 100644
--- a/library/Notifications/Model/ContactAddress.php
+++ b/library/Notifications/Model/ContactAddress.php
@@ -4,9 +4,24 @@
 
 namespace Icinga\Module\Notifications\Model;
 
+use DateTime;
+use ipl\Orm\Behavior\BoolCast;
+use ipl\Orm\Behavior\MillisecondTimestamp;
+use ipl\Orm\Behaviors;
 use ipl\Orm\Model;
+use ipl\Orm\Query;
 use ipl\Orm\Relations;
 
+/**
+ * @property int $id
+ * @property int $contact_id
+ * @property string $type
+ * @property string $address
+ * @property DateTime $changed_at
+ * @property bool $deleted
+ *
+ * @property Query|Contact $contact
+ */
 class ContactAddress extends Model
 {
     public function getTableName(): string
@@ -24,11 +39,19 @@ public function getColumns(): array
         return [
             'contact_id',
             'type',
-            'address'
+            'address',
+            'changed_at',
+            'deleted'
         ];
     }
 
-    public function createRelations(Relations $relations)
+    public function createBehaviors(Behaviors $behaviors): void
+    {
+        $behaviors->add(new MillisecondTimestamp(['changed_at']));
+        $behaviors->add(new BoolCast(['deleted']));
+    }
+
+    public function createRelations(Relations $relations): void
     {
         $relations->belongsTo('contact', Contact::class);
     }
diff --git a/library/Notifications/Model/Contactgroup.php b/library/Notifications/Model/Contactgroup.php
index aac6ab6d..3dc79481 100644
--- a/library/Notifications/Model/Contactgroup.php
+++ b/library/Notifications/Model/Contactgroup.php
@@ -4,6 +4,10 @@
 
 namespace Icinga\Module\Notifications\Model;
 
+use DateTime;
+use ipl\Orm\Behavior\BoolCast;
+use ipl\Orm\Behavior\MillisecondTimestamp;
+use ipl\Orm\Behaviors;
 use ipl\Orm\Model;
 use ipl\Orm\Query;
 use ipl\Orm\Relations;
@@ -11,12 +15,15 @@
 /**
  * Contact group
  *
- * @param int $id
- * @param string $name
+ * @property int $id
+ * @property string $name
+ * @property DateTime $changed_at
+ * @property bool $deleted
  *
- * @property Query | Contact $contact
- * @property Query | RuleEscalationRecipient $rule_escalation_recipient
- * @property Query | IncidentHistory $incident_history
+ * @property Query|Contact $contact
+ * @property Query|ContactgroupMember $contactgroup_member
+ * @property Query|RuleEscalationRecipient $rule_escalation_recipient
+ * @property Query|IncidentHistory $incident_history
  */
 class Contactgroup extends Model
 {
@@ -33,7 +40,9 @@ public function getKeyName(): string
     public function getColumns(): array
     {
         return [
-            'name'
+            'name',
+            'changed_at',
+            'deleted'
         ];
     }
 
@@ -47,11 +56,18 @@ public function getSearchColumns(): array
         return ['name'];
     }
 
+    public function createBehaviors(Behaviors $behaviors): void
+    {
+        $behaviors->add(new MillisecondTimestamp(['changed_at']));
+        $behaviors->add(new BoolCast(['deleted']));
+    }
+
     public function createRelations(Relations $relations): void
     {
         $relations->hasMany('rule_escalation_recipient', RuleEscalationRecipient::class)
             ->setJoinType('LEFT');
         $relations->hasMany('incident_history', IncidentHistory::class);
+        $relations->hasMany('contactgroup_member', ContactgroupMember::class);
         $relations
             ->belongsToMany('contact', Contact::class)
             ->through('contactgroup_member')
diff --git a/library/Notifications/Model/ContactgroupMember.php b/library/Notifications/Model/ContactgroupMember.php
new file mode 100644
index 00000000..97741c8c
--- /dev/null
+++ b/library/Notifications/Model/ContactgroupMember.php
@@ -0,0 +1,59 @@
+<?php
+
+/* Icinga Notifications Web | (c) 2023 Icinga GmbH | GPLv2 */
+
+namespace Icinga\Module\Notifications\Model;
+
+use DateTime;
+use ipl\Orm\Behavior\BoolCast;
+use ipl\Orm\Behavior\MillisecondTimestamp;
+use ipl\Orm\Behaviors;
+use ipl\Orm\Model;
+use ipl\Orm\Query;
+use ipl\Orm\Relations;
+
+/**
+ * Contactgroup Member
+ *
+ * @param int $contactgroup_id
+ * @param int $contact_id
+ * @param DateTime $changed_at
+ * @param bool $deleted
+ *
+ * @property Query|Contactgroup $contactgroup
+ * @property Query|Contact $contact
+ */
+class ContactgroupMember extends Model
+{
+    public function getTableName(): string
+    {
+        return 'contactgroup_member';
+    }
+
+    public function getKeyName(): array
+    {
+        return ['contactgroup_id', 'contact_id'];
+    }
+
+    public function getColumns(): array
+    {
+        return [
+            'contactgroup_id',
+            'contact_id',
+            'changed_at',
+            'deleted'
+        ];
+    }
+
+    public function createBehaviors(Behaviors $behaviors): void
+    {
+        $behaviors->add(new MillisecondTimestamp(['changed_at']));
+        $behaviors->add(new BoolCast(['deleted']));
+    }
+
+    public function createRelations(Relations $relations): void
+    {
+        $relations->belongsTo('contactgroup', Contactgroup::class);
+        $relations->belongsTo('contact', Contact::class);
+    }
+}
diff --git a/library/Notifications/Model/Event.php b/library/Notifications/Model/Event.php
index 56aeacb4..6aea53bc 100644
--- a/library/Notifications/Model/Event.php
+++ b/library/Notifications/Model/Event.php
@@ -31,23 +31,23 @@
  * @property ?bool $mute
  * @property ?string $mute_reason
  *
- * @property Query | Objects $object
- * @property Query | IncidentHistory $incident_history
- * @property Query | Incident $incident
+ * @property Query|Objects $object
+ * @property Query|IncidentHistory $incident_history
+ * @property Query|Incident $incident
  */
 class Event extends Model
 {
-    public function getTableName()
+    public function getTableName(): string
     {
         return 'event';
     }
 
-    public function getKeyName()
+    public function getKeyName(): string
     {
         return 'id';
     }
 
-    public function getColumns()
+    public function getColumns(): array
     {
         return [
             'time',
@@ -61,7 +61,7 @@ public function getColumns()
         ];
     }
 
-    public function getColumnDefinitions()
+    public function getColumnDefinitions(): array
     {
         return [
             'time'      => t('Received On'),
@@ -75,17 +75,17 @@ public function getColumnDefinitions()
         ];
     }
 
-    public function getSearchColumns()
+    public function getSearchColumns(): array
     {
         return ['object.name'];
     }
 
-    public function getDefaultSort()
+    public function getDefaultSort(): string
     {
         return 'event.time';
     }
 
-    public static function on(Connection $db)
+    public static function on(Connection $db): Query
     {
         $query = parent::on($db);
 
@@ -98,14 +98,14 @@ public static function on(Connection $db)
         return $query;
     }
 
-    public function createBehaviors(Behaviors $behaviors)
+    public function createBehaviors(Behaviors $behaviors): void
     {
         $behaviors->add(new MillisecondTimestamp(['time']));
         $behaviors->add(new Binary(['object_id']));
         $behaviors->add(new BoolCast(['mute']));
     }
 
-    public function createRelations(Relations $relations)
+    public function createRelations(Relations $relations): void
     {
         $relations->belongsTo('object', Objects::class)->setJoinType('LEFT');
 
diff --git a/library/Notifications/Model/Incident.php b/library/Notifications/Model/Incident.php
index 408786b2..4f86e1d7 100644
--- a/library/Notifications/Model/Incident.php
+++ b/library/Notifications/Model/Incident.php
@@ -24,27 +24,27 @@
  * @property ?DateTime $recovered_at
  * @property string $severity
  *
- * @property Query | Objects $object
- * @property Query | Event $event
- * @property Query | Contact $contact
- * @property Query | IncidentContact $incident_contact
- * @property Query | IncidentHistory $incident_history
- * @property Query | Rule $rule
- * @property Query | RuleEscalation $rule_escalation
+ * @property Query|Objects $object
+ * @property Query|Event $event
+ * @property Query|Contact $contact
+ * @property Query|IncidentContact $incident_contact
+ * @property Query|IncidentHistory $incident_history
+ * @property Query|Rule $rule
+ * @property Query|RuleEscalation $rule_escalation
  */
 class Incident extends Model
 {
-    public function getTableName()
+    public function getTableName(): string
     {
         return 'incident';
     }
 
-    public function getKeyName()
+    public function getKeyName(): string
     {
         return 'id';
     }
 
-    public function getColumns()
+    public function getColumns(): array
     {
         return [
             'object_id',
@@ -54,7 +54,7 @@ public function getColumns()
         ];
     }
 
-    public function getColumnDefinitions()
+    public function getColumnDefinitions(): array
     {
         return [
             'object_id'    => t('Object Id'),
@@ -64,17 +64,17 @@ public function getColumnDefinitions()
         ];
     }
 
-    public function getSearchColumns()
+    public function getSearchColumns(): array
     {
         return ['object.name'];
     }
 
-    public function getDefaultSort()
+    public function getDefaultSort(): array
     {
         return ['incident.severity desc, incident.started_at'];
     }
 
-    public static function on(Connection $db)
+    public static function on(Connection $db): Query
     {
         $query = parent::on($db);
 
@@ -87,7 +87,7 @@ public static function on(Connection $db)
         return $query;
     }
 
-    public function createBehaviors(Behaviors $behaviors)
+    public function createBehaviors(Behaviors $behaviors): void
     {
         $behaviors->add(new Binary(['object_id']));
         $behaviors->add(new MillisecondTimestamp([
@@ -96,7 +96,7 @@ public function createBehaviors(Behaviors $behaviors)
         ]));
     }
 
-    public function createRelations(Relations $relations)
+    public function createRelations(Relations $relations): void
     {
         $relations->belongsTo('object', Objects::class);
 
diff --git a/library/Notifications/Model/IncidentContact.php b/library/Notifications/Model/IncidentContact.php
index 22b63ca4..c1dfc35f 100644
--- a/library/Notifications/Model/IncidentContact.php
+++ b/library/Notifications/Model/IncidentContact.php
@@ -5,21 +5,30 @@
 namespace Icinga\Module\Notifications\Model;
 
 use ipl\Orm\Model;
+use ipl\Orm\Query;
 use ipl\Orm\Relations;
 
+/**
+ * @property int $incident_id
+ * @property ?int $contact_id
+ * @property string $role
+ *
+ * @property Query|Incident $incident
+ * @property Query|Contact $contact
+ */
 class IncidentContact extends Model
 {
-    public function getTableName()
+    public function getTableName(): string
     {
         return 'incident_contact';
     }
 
-    public function getKeyName()
+    public function getKeyName(): array
     {
         return ['incident_id', 'contact_id'];
     }
 
-    public function getColumns()
+    public function getColumns(): array
     {
         return [
             'incident_id',
@@ -28,7 +37,7 @@ public function getColumns()
         ];
     }
 
-    public function getColumnDefinitions()
+    public function getColumnDefinitions(): array
     {
         return [
             'incident_id'   => t('Incident Id'),
@@ -37,7 +46,7 @@ public function getColumnDefinitions()
         ];
     }
 
-    public function createRelations(Relations $relations)
+    public function createRelations(Relations $relations): void
     {
         $relations->belongsTo('incident', Incident::class);
         $relations->belongsTo('contact', Contact::class);
diff --git a/library/Notifications/Model/IncidentHistory.php b/library/Notifications/Model/IncidentHistory.php
index 320eb7cd..c8bcec66 100644
--- a/library/Notifications/Model/IncidentHistory.php
+++ b/library/Notifications/Model/IncidentHistory.php
@@ -25,37 +25,39 @@
  * @property DateTime $time
  * @property string $type
  * @property ?int $contact_id
+ * @property ?int $schedule_id
+ * @property ?int $contactgroup_id
  * @property ?int $channel_id
  * @property ?string $new_severity
  * @property ?string $old_severity
  * @property ?string $new_recipient_role
  * @property ?string $old_recipient_role
  * @property ?string $message
- * @property string $notification_state
- * @property DateTime $sent_at
+ * @property ?string $notification_state
+ * @property ?DateTime $sent_at
  *
- * @property Query | Incident $incident
- * @property Query | Event $event
- * @property Query | Contact $contact
- * @property Query | Contactgroup $contactgroup
- * @property Query | Schedule $schedule
- * @property Query | Rule $rule
- * @property Query | RuleEscalation $rule_escalation
- * @property Query | Channel $channel
+ * @property Query|Incident $incident
+ * @property Query|Event $event
+ * @property Query|Contact $contact
+ * @property Query|Contactgroup $contactgroup
+ * @property Query|Schedule $schedule
+ * @property Query|Rule $rule
+ * @property Query|RuleEscalation $rule_escalation
+ * @property Query|Channel $channel
  */
 class IncidentHistory extends Model
 {
-    public function getTableName()
+    public function getTableName(): string
     {
         return 'incident_history';
     }
 
-    public function getKeyName()
+    public function getKeyName(): string
     {
         return 'id';
     }
 
-    public function getColumns()
+    public function getColumns(): array
     {
         return [
             'incident_id',
@@ -78,7 +80,7 @@ public function getColumns()
         ];
     }
 
-    public function getColumnDefinitions()
+    public function getColumnDefinitions(): array
     {
         return [
             'incident_id'        => t('Incident Id'),
@@ -98,17 +100,17 @@ public function getColumnDefinitions()
         ];
     }
 
-    public function createBehaviors(Behaviors $behaviors)
+    public function createBehaviors(Behaviors $behaviors): void
     {
         $behaviors->add(new MillisecondTimestamp(['time', 'sent_at']));
     }
 
-    public function getDefaultSort()
+    public function getDefaultSort(): array
     {
         return ['incident_history.time desc, incident_history.type desc'];
     }
 
-    public static function on(Connection $db)
+    public static function on(Connection $db): Query
     {
         $query = parent::on($db);
 
@@ -121,7 +123,7 @@ public static function on(Connection $db)
         return $query;
     }
 
-    public function createRelations(Relations $relations)
+    public function createRelations(Relations $relations): void
     {
         $relations->belongsTo('incident', Incident::class);
 
diff --git a/library/Notifications/Model/ObjectExtraTag.php b/library/Notifications/Model/ObjectExtraTag.php
index fc172ab6..df7beb73 100644
--- a/library/Notifications/Model/ObjectExtraTag.php
+++ b/library/Notifications/Model/ObjectExtraTag.php
@@ -7,28 +7,31 @@
 use ipl\Orm\Behavior\Binary;
 use ipl\Orm\Behaviors;
 use ipl\Orm\Model;
+use ipl\Orm\Query;
 use ipl\Orm\Relations;
 
 /**
  * ObjectExtraTag database model
  *
- * @property int $object_id
+ * @property string $object_id
  * @property string $tag
  * @property string $value
+ *
+ * @property Query|Objects $object
  */
 class ObjectExtraTag extends Model
 {
-    public function getTableName()
+    public function getTableName(): string
     {
         return 'object_extra_tag';
     }
 
-    public function getKeyName()
+    public function getKeyName(): array
     {
         return ['object_id', 'tag'];
     }
 
-    public function getColumns()
+    public function getColumns(): array
     {
         return [
             'object_id',
@@ -37,12 +40,12 @@ public function getColumns()
         ];
     }
 
-    public function createBehaviors(Behaviors $behaviors)
+    public function createBehaviors(Behaviors $behaviors): void
     {
         $behaviors->add(new Binary(['object_id']));
     }
 
-    public function createRelations(Relations $relations)
+    public function createRelations(Relations $relations): void
     {
         $relations->belongsTo('object', Objects::class);
     }
diff --git a/library/Notifications/Model/ObjectIdTag.php b/library/Notifications/Model/ObjectIdTag.php
index b0d33621..8a26ea79 100644
--- a/library/Notifications/Model/ObjectIdTag.php
+++ b/library/Notifications/Model/ObjectIdTag.php
@@ -12,7 +12,7 @@
 /**
  * ObjectIdTag database model
  *
- * @property int $object_id
+ * @property string $object_id
  * @property string $tag
  * @property string $value
  */
@@ -23,7 +23,7 @@ public function getTableName(): string
         return 'object_id_tag';
     }
 
-    public function getKeyName()
+    public function getKeyName(): array
     {
         return ['object_id', 'tag'];
     }
diff --git a/library/Notifications/Model/Objects.php b/library/Notifications/Model/Objects.php
index 68d43e3b..c6210565 100644
--- a/library/Notifications/Model/Objects.php
+++ b/library/Notifications/Model/Objects.php
@@ -19,32 +19,30 @@
  * @property string $id
  * @property int $source_id
  * @property string $name
- * @property string $host
- * @property ?string $service
  * @property ?string $url
  * @property ?string $mute_reason
  *
- * @property Query | Event $event
- * @property Query | Incident $incident
- * @property Query | Tag $tag
- * @property Query | ObjectExtraTag $object_extra_tag
- * @property Query | ExtraTag $extra_tag
- * @property Query | Source $source
+ * @property Query|Event $event
+ * @property Query|Incident $incident
+ * @property Query|Tag $tag
+ * @property Query|ObjectExtraTag $object_extra_tag
+ * @property Query|ExtraTag $extra_tag
+ * @property Query|Source $source
  * @property array<string, string> $id_tags
  */
 class Objects extends Model
 {
-    public function getTableName()
+    public function getTableName(): string
     {
         return 'object';
     }
 
-    public function getKeyName()
+    public function getKeyName(): string
     {
         return 'id';
     }
 
-    public function getColumns()
+    public function getColumns(): array
     {
         return [
             'source_id',
@@ -57,7 +55,7 @@ public function getColumns()
     /**
      * @return string[]
      */
-    public function getSearchColumns()
+    public function getSearchColumns(): array
     {
         return ['object_id_tag.tag', 'object_id_tag.value'];
     }
@@ -65,18 +63,18 @@ public function getSearchColumns()
     /**
      * @return string
      */
-    public function getDefaultSort()
+    public function getDefaultSort(): string
     {
         return 'object.name';
     }
 
-    public function createBehaviors(Behaviors $behaviors)
+    public function createBehaviors(Behaviors $behaviors): void
     {
         $behaviors->add(new Binary(['id']));
         $behaviors->add(new IdTagAggregator());
     }
 
-    public function createRelations(Relations $relations)
+    public function createRelations(Relations $relations): void
     {
         $relations->hasMany('event', Event::class);
         $relations->hasMany('incident', Incident::class);
diff --git a/library/Notifications/Model/Rotation.php b/library/Notifications/Model/Rotation.php
index 9c0c4d82..46a3901b 100644
--- a/library/Notifications/Model/Rotation.php
+++ b/library/Notifications/Model/Rotation.php
@@ -5,25 +5,32 @@
 namespace Icinga\Module\Notifications\Model;
 
 use DateTime;
+use Icinga\Module\Notifications\Common\Database;
+use Icinga\Module\Notifications\Forms\RotationConfigForm;
 use Icinga\Util\Json;
+use ipl\Orm\Behavior\BoolCast;
 use ipl\Orm\Behavior\MillisecondTimestamp;
 use ipl\Orm\Behaviors;
 use ipl\Orm\Contract\RetrieveBehavior;
 use ipl\Orm\Model;
 use ipl\Orm\Query;
 use ipl\Orm\Relations;
+use ipl\Sql\Expression;
+use ipl\Stdlib\Filter;
 
 /**
  * Rotation
  *
  * @property int $id
  * @property int $schedule_id
- * @property int $priority
+ * @property ?int $priority
  * @property string $name
  * @property string $mode
  * @property string|array $options
  * @property string $first_handoff
  * @property DateTime $actual_handoff
+ * @property DateTime $changed_at
+ * @property bool $deleted
  *
  * @property Query|Schedule $schedule
  * @property Query|RotationMember $member
@@ -31,17 +38,17 @@
  */
 class Rotation extends Model
 {
-    public function getTableName()
+    public function getTableName(): string
     {
         return 'rotation';
     }
 
-    public function getKeyName()
+    public function getKeyName(): string
     {
         return 'id';
     }
 
-    public function getColumns()
+    public function getColumns(): array
     {
         return [
             'schedule_id',
@@ -50,23 +57,26 @@ public function getColumns()
             'mode',
             'options',
             'first_handoff',
-            'actual_handoff'
+            'actual_handoff',
+            'changed_at',
+            'deleted'
         ];
     }
 
-    public function getColumnDefinitions()
+    public function getColumnDefinitions(): array
     {
         return [
-            'schedule_id' => t('Schedule'),
-            'priority' => t('Priority'),
-            'name' => t('Name'),
-            'mode' => t('Mode'),
-            'first_handoff' => t('First Handoff'),
-            'actual_handoff' => t('Actual Handoff')
+            'schedule_id'       => t('Schedule'),
+            'priority'          => t('Priority'),
+            'name'              => t('Name'),
+            'mode'              => t('Mode'),
+            'first_handoff'     => t('First Handoff'),
+            'actual_handoff'    => t('Actual Handoff'),
+            'changed_at'        => t('Changed At')
         ];
     }
 
-    public function createRelations(Relations $relations)
+    public function createRelations(Relations $relations): void
     {
         $relations->belongsTo('schedule', Schedule::class);
 
@@ -76,11 +86,13 @@ public function createRelations(Relations $relations)
             ->setForeignKey('owned_by_rotation_id');
     }
 
-    public function createBehaviors(Behaviors $behaviors)
+    public function createBehaviors(Behaviors $behaviors): void
     {
         $behaviors->add(new MillisecondTimestamp([
-            'actual_handoff'
+            'actual_handoff',
+            'changed_at'
         ]));
+        $behaviors->add(new BoolCast(['deleted']));
         $behaviors->add(new class implements RetrieveBehavior {
             public function retrieve(Model $model): void
             {
@@ -91,4 +103,74 @@ public function retrieve(Model $model): void
             }
         });
     }
+
+    /**
+     * Delete rotation and all related references
+     *
+     * @return void
+     */
+    public function delete(): void
+    {
+        $db = Database::get();
+        $transactionStarted = false;
+        if (! $db->inTransaction()) {
+            $transactionStarted = true;
+            $db->beginTransaction();
+        }
+
+        if ($this->timeperiod instanceof Timeperiod) {
+            $timeperiodId = $this->timeperiod->id;
+        } else {
+            $timeperiodId = $this->timeperiod->columns('id')->first()->id;
+        }
+
+        $changedAt = time() * 1000;
+        $markAsDeleted = ['changed_at' => $changedAt, 'deleted' => 'y'];
+
+        $db->update('timeperiod_entry', $markAsDeleted, ['timeperiod_id = ?' => $timeperiodId,  'deleted = ?' => 'n']);
+        $db->update('timeperiod', $markAsDeleted, ['id = ?' => $timeperiodId]);
+
+        $db->update(
+            'rotation_member',
+            $markAsDeleted + ['position' => null],
+            ['rotation_id = ?' => $this->id, 'deleted = ?' => 'n']
+        );
+
+        $db->update(
+            'rotation',
+            $markAsDeleted + ['priority' => null, 'first_handoff' => null],
+            ['id = ?' => $this->id]
+        );
+
+        $requirePriorityUpdate = true;
+        if (RotationConfigForm::EXPERIMENTAL_OVERRIDES) {
+            $rotations = self::on($db)
+                ->columns('1')
+                ->filter(Filter::equal('schedule_id', $this->schedule_id))
+                ->filter(Filter::equal('priority', $this->priority))
+                ->first();
+
+            $requirePriorityUpdate = $rotations === null;
+        }
+
+        if ($requirePriorityUpdate) {
+            $affectedRotations = self::on($db)
+                ->columns('id')
+                ->filter(Filter::equal('schedule_id', $this->schedule_id))
+                ->filter(Filter::greaterThan('priority', $this->priority))
+                ->orderBy('priority', SORT_ASC);
+
+            foreach ($affectedRotations as $rotation) {
+                $db->update(
+                    'rotation',
+                    ['priority' => new Expression('priority - 1'), 'changed_at' => $changedAt],
+                    ['id = ?' => $rotation->id]
+                );
+            }
+        }
+
+        if ($transactionStarted) {
+            $db->commitTransaction();
+        }
+    }
 }
diff --git a/library/Notifications/Model/RotationMember.php b/library/Notifications/Model/RotationMember.php
index 5f5212a5..69573b35 100644
--- a/library/Notifications/Model/RotationMember.php
+++ b/library/Notifications/Model/RotationMember.php
@@ -4,6 +4,10 @@
 
 namespace Icinga\Module\Notifications\Model;
 
+use DateTime;
+use ipl\Orm\Behavior\BoolCast;
+use ipl\Orm\Behavior\MillisecondTimestamp;
+use ipl\Orm\Behaviors;
 use ipl\Orm\Model;
 use ipl\Orm\Query;
 use ipl\Orm\Relations;
@@ -15,7 +19,9 @@
  * @property int $rotation_id
  * @property ?int $contact_id
  * @property ?int $contactgroup_id
- * @property int $position
+ * @property ?int $position
+ * @property DateTime $changed_at
+ * @property bool $deleted
  *
  * @property Query|Rotation $rotation
  * @property Query|Contact $contact
@@ -24,27 +30,35 @@
  */
 class RotationMember extends Model
 {
-    public function getTableName()
+    public function getTableName(): string
     {
         return 'rotation_member';
     }
 
-    public function getKeyName()
+    public function getKeyName(): string
     {
         return 'id';
     }
 
-    public function getColumns()
+    public function getColumns(): array
     {
         return [
             'rotation_id',
             'contact_id',
             'contactgroup_id',
-            'position'
+            'position',
+            'changed_at',
+            'deleted'
         ];
     }
 
-    public function createRelations(Relations $relations)
+    public function createBehaviors(Behaviors $behaviors): void
+    {
+        $behaviors->add(new MillisecondTimestamp(['changed_at']));
+        $behaviors->add(new BoolCast(['deleted']));
+    }
+
+    public function createRelations(Relations $relations): void
     {
         $relations->belongsTo('rotation', Rotation::class);
         $relations->belongsTo('contact', Contact::class)
diff --git a/library/Notifications/Model/Rule.php b/library/Notifications/Model/Rule.php
index 158b2228..8e69a014 100644
--- a/library/Notifications/Model/Rule.php
+++ b/library/Notifications/Model/Rule.php
@@ -4,52 +4,76 @@
 
 namespace Icinga\Module\Notifications\Model;
 
+use DateTime;
+use ipl\Orm\Behavior\BoolCast;
+use ipl\Orm\Behavior\MillisecondTimestamp;
+use ipl\Orm\Behaviors;
 use ipl\Orm\Model;
+use ipl\Orm\Query;
 use ipl\Orm\Relations;
 
+/**
+ * @property int $id
+ * @property string $name
+ * @property ?int $timeperiod_id
+ * @property ?string $object_filter
+ * @property DateTime $changed_at
+ * @property bool $deleted
+ *
+ * @property Query|RuleEscalation $rule_escalation
+ * @property Query|Incident $incident
+ * @property Query|IncidentHistory $incident_history
+ */
 class Rule extends Model
 {
-    public function getTableName()
+    public function getTableName(): string
     {
         return 'rule';
     }
 
-    public function getKeyName()
+    public function getKeyName(): string
     {
         return 'id';
     }
 
-    public function getColumns()
+    public function getColumns(): array
     {
         return [
             'name',
             'timeperiod_id',
             'object_filter',
-            'is_active'
+            'changed_at',
+            'deleted'
         ];
     }
 
-    public function getColumnDefinitions()
+    public function getColumnDefinitions(): array
     {
         return [
             'name'          => t('Name'),
             'timeperiod_id' => t('Timeperiod ID'),
             'object_filter' => t('Object Filter'),
-            'is_active'     => t('Is Active')
+            'changed_at'    => t('Changed At')
         ];
     }
 
-    public function getSearchColumns()
+    public function getSearchColumns(): array
     {
         return ['name'];
     }
 
-    public function getDefaultSort()
+    public function getDefaultSort(): array
     {
         return ['name'];
     }
 
-    public function createRelations(Relations $relations)
+    public function createBehaviors(Behaviors $behaviors): void
+    {
+        $behaviors->add(new MillisecondTimestamp(['changed_at']));
+        $behaviors->add(new BoolCast(['deleted']));
+    }
+
+    public function createRelations(Relations $relations): void
     {
         $relations->hasMany('rule_escalation', RuleEscalation::class);
 
diff --git a/library/Notifications/Model/RuleEscalation.php b/library/Notifications/Model/RuleEscalation.php
index 78064eb6..5276308e 100644
--- a/library/Notifications/Model/RuleEscalation.php
+++ b/library/Notifications/Model/RuleEscalation.php
@@ -4,54 +4,85 @@
 
 namespace Icinga\Module\Notifications\Model;
 
+use DateTime;
+use ipl\Orm\Behavior\BoolCast;
+use ipl\Orm\Behavior\MillisecondTimestamp;
+use ipl\Orm\Behaviors;
 use ipl\Orm\Model;
+use ipl\Orm\Query;
 use ipl\Orm\Relations;
 
+/**
+ * @property int $id
+ * @property int $rule_id
+ * @property ?int $position
+ * @property ?string $condition
+ * @property ?string $name
+ * @property ?string $fallback_for
+ * @property DateTime $changed_at
+ * @property bool $deleted
+ *
+ * @property Query|Rule $rule
+ * @property Query|Incident $incident
+ * @property Query|Contact $contact
+ * @property Query|RuleEscalationRecipient $rule_escalation_recipient
+ * @property Query|IncidentHistory $incident_history
+ */
 class RuleEscalation extends Model
 {
-    public function getTableName()
+    public function getTableName(): string
     {
         return 'rule_escalation';
     }
 
-    public function getKeyName()
+    public function getKeyName(): string
     {
         return 'id';
     }
 
-    public function getColumns()
+    public function getColumns(): array
     {
         return [
             'rule_id',
             'position',
             'condition',
             'name',
-            'fallback_for'
+            'fallback_for',
+            'changed_at',
+            'deleted'
         ];
     }
 
-    public function getColumnDefinitions()
+    public function getColumnDefinitions(): array
     {
         return [
             'rule_id'       => t('Rule ID'),
             'position'      => t('Position'),
             'condition'     => t('Condition'),
             'name'          => t('Name'),
-            'fallback_for'  => t('Fallback For')
+            'fallback_for'  => t('Fallback For'),
+            'changed_at'    => t('Changed At')
         ];
     }
 
-    public function getSearchColumns()
+    public function getSearchColumns(): array
     {
         return ['name'];
     }
 
-    public function getDefaultSort()
+    public function getDefaultSort(): array
     {
         return ['position'];
     }
 
-    public function createRelations(Relations $relations)
+
+    public function createBehaviors(Behaviors $behaviors): void
+    {
+        $behaviors->add(new MillisecondTimestamp(['changed_at']));
+        $behaviors->add(new BoolCast(['deleted']));
+    }
+
+    public function createRelations(Relations $relations): void
     {
         $relations->belongsTo('rule', Rule::class);
 
diff --git a/library/Notifications/Model/RuleEscalationRecipient.php b/library/Notifications/Model/RuleEscalationRecipient.php
index a1f4bdcb..a3cc2660 100644
--- a/library/Notifications/Model/RuleEscalationRecipient.php
+++ b/library/Notifications/Model/RuleEscalationRecipient.php
@@ -4,49 +4,80 @@
 
 namespace Icinga\Module\Notifications\Model;
 
+use DateTime;
+use ipl\Orm\Behavior\BoolCast;
+use ipl\Orm\Behavior\MillisecondTimestamp;
+use ipl\Orm\Behaviors;
 use ipl\Orm\Model;
+use ipl\Orm\Query;
 use ipl\Orm\Relations;
 
+/**
+ * @property int $id
+ * @property int $rule_escalation_id
+ * @property ?int $contact_id
+ * @property ?int $contactgroup_id
+ * @property ?int $schedule_id
+ * @property ?int $channel_id
+ * @property DateTime $changed_at
+ * @property bool $deleted
+ *
+ * @property Query|RuleEscalation $rule_escalation
+ * @property Query|Contact $contact
+ * @property Query|Schedule $schedule
+ * @property Query|Contactgroup $contactgroup
+ * @property Query|Channel $channel
+ */
+
 class RuleEscalationRecipient extends Model
 {
-    public function getTableName()
+    public function getTableName(): string
     {
         return 'rule_escalation_recipient';
     }
 
-    public function getKeyName()
+    public function getKeyName(): string
     {
         return 'id';
     }
 
-    public function getColumns()
+    public function getColumns(): array
     {
         return [
             'rule_escalation_id',
             'contact_id',
             'contactgroup_id',
             'schedule_id',
-            'channel_id'
+            'channel_id',
+            'changed_at',
+            'deleted'
         ];
     }
 
-    public function getColumnDefinitions()
+    public function getColumnDefinitions(): array
     {
         return [
             'rule_escalation_id' => t('Rule Escalation ID'),
             'contact_id'         => t('Contact ID'),
             'contactgroup_id'    => t('Contactgroup ID'),
             'schedule_id'        => t('Schedule ID'),
-            'channel_id'         => t('Channel ID')
+            'channel_id'         => t('Channel ID'),
+            'changed_at'         => t('Changed At')
         ];
     }
 
-    public function getDefaultSort()
+    public function getDefaultSort(): array
     {
         return ['rule_escalation_id'];
     }
 
-    public function createRelations(Relations $relations)
+    public function createBehaviors(Behaviors $behaviors): void
+    {
+        $behaviors->add(new MillisecondTimestamp(['changed_at']));
+        $behaviors->add(new BoolCast(['deleted']));
+    }
+
+    public function createRelations(Relations $relations): void
     {
         $relations->belongsTo('rule_escalation', RuleEscalation::class);
         $relations->belongsTo('contact', Contact::class);
@@ -58,9 +89,9 @@ public function createRelations(Relations $relations)
     /**
      * Get the recipient model
      *
-     * @return ?Model
+     * @return Contact|Contactgroup|Schedule|null
      */
-    public function getRecipient()
+    public function getRecipient(): ?Model
     {
         $recipientModel = null;
         if ($this->contact_id) {
diff --git a/library/Notifications/Model/Schedule.php b/library/Notifications/Model/Schedule.php
index ebad9c84..c3f82339 100644
--- a/library/Notifications/Model/Schedule.php
+++ b/library/Notifications/Model/Schedule.php
@@ -4,6 +4,10 @@
 
 namespace Icinga\Module\Notifications\Model;
 
+use DateTime;
+use ipl\Orm\Behavior\BoolCast;
+use ipl\Orm\Behavior\MillisecondTimestamp;
+use ipl\Orm\Behaviors;
 use ipl\Orm\Model;
 use ipl\Orm\Query;
 use ipl\Orm\Relations;
@@ -11,10 +15,12 @@
 /**
  * @property int $id
  * @property string $name
+ * @property DateTime $changed_at
+ * @property bool $deleted
  *
- * @property Rotation|Query $rotation
- * @property RuleEscalationRecipient|Query $rule_escalation_recipient
- * @property IncidentHistory|Query $incident_history
+ * @property Query|Rotation $rotation
+ * @property Query|RuleEscalationRecipient $rule_escalation_recipient
+ * @property Query|IncidentHistory $incident_history
  */
 class Schedule extends Model
 {
@@ -31,13 +37,18 @@ public function getKeyName(): string
     public function getColumns(): array
     {
         return [
-            'name'
+            'name',
+            'changed_at',
+            'deleted'
         ];
     }
 
     public function getColumnDefinitions(): array
     {
-        return ['name' => t('Name')];
+        return [
+            'name'          => t('Name'),
+            'changed_at'    => t('Changed At')
+        ];
     }
 
     public function getSearchColumns(): array
@@ -50,6 +61,12 @@ public function getDefaultSort(): string
         return 'name';
     }
 
+    public function createBehaviors(Behaviors $behaviors): void
+    {
+        $behaviors->add(new MillisecondTimestamp(['changed_at']));
+        $behaviors->add(new BoolCast(['deleted']));
+    }
+
     public function createRelations(Relations $relations): void
     {
         $relations->hasMany('rotation', Rotation::class);
diff --git a/library/Notifications/Model/Source.php b/library/Notifications/Model/Source.php
index 823c6715..973bbb76 100644
--- a/library/Notifications/Model/Source.php
+++ b/library/Notifications/Model/Source.php
@@ -4,7 +4,12 @@
 
 namespace Icinga\Module\Notifications\Model;
 
+use DateTime;
+use ipl\Orm\Behavior\BoolCast;
+use ipl\Orm\Behavior\MillisecondTimestamp;
+use ipl\Orm\Behaviors;
 use ipl\Orm\Model;
+use ipl\Orm\Query;
 use ipl\Orm\Relations;
 use ipl\Web\Widget\IcingaIcon;
 use ipl\Web\Widget\Icon;
@@ -20,23 +25,27 @@
  * @property ?string $icinga2_ca_pem
  * @property ?string $icinga2_common_name
  * @property string $icinga2_insecure_tls
+ * @property DateTime $changed_at
+ * @property bool $deleted
+ *
+ * @property Query|Objects $object
  */
 class Source extends Model
 {
     /** @var string The type name used by Icinga sources */
     public const ICINGA_TYPE_NAME = 'icinga2';
 
-    public function getTableName()
+    public function getTableName(): string
     {
         return 'source';
     }
 
-    public function getKeyName()
+    public function getKeyName(): string
     {
         return 'id';
     }
 
-    public function getColumns()
+    public function getColumns(): array
     {
         return [
             'type',
@@ -47,29 +56,38 @@ public function getColumns()
             'icinga2_auth_pass',
             'icinga2_ca_pem',
             'icinga2_common_name',
-            'icinga2_insecure_tls'
+            'icinga2_insecure_tls',
+            'changed_at',
+            'deleted'
         ];
     }
 
-    public function getColumnDefinitions()
+    public function getColumnDefinitions(): array
     {
         return [
-            'type' => t('Type'),
-            'name' => t('Name')
+            'type'          => t('Type'),
+            'name'          => t('Name'),
+            'changed_at'    => t('Changed At')
         ];
     }
 
-    public function getSearchColumns()
+    public function getSearchColumns(): array
     {
         return ['type'];
     }
 
-    public function getDefaultSort()
+    public function getDefaultSort(): string
     {
         return 'source.name';
     }
 
-    public function createRelations(Relations $relations)
+    public function createBehaviors(Behaviors $behaviors): void
+    {
+        $behaviors->add(new MillisecondTimestamp(['changed_at']));
+        $behaviors->add(new BoolCast(['deleted']));
+    }
+
+    public function createRelations(Relations $relations): void
     {
         $relations->hasMany('object', Objects::class);
     }
diff --git a/library/Notifications/Model/Timeperiod.php b/library/Notifications/Model/Timeperiod.php
index 28be50ca..c270341a 100644
--- a/library/Notifications/Model/Timeperiod.php
+++ b/library/Notifications/Model/Timeperiod.php
@@ -4,6 +4,10 @@
 
 namespace Icinga\Module\Notifications\Model;
 
+use DateTime;
+use ipl\Orm\Behavior\BoolCast;
+use ipl\Orm\Behavior\MillisecondTimestamp;
+use ipl\Orm\Behaviors;
 use ipl\Orm\Model;
 use ipl\Orm\Query;
 use ipl\Orm\Relations;
@@ -13,30 +17,40 @@
  *
  * @property int $id
  * @property ?int $owned_by_rotation_id
+ * @property DateTime $changed_at
+ * @property bool $deleted
  *
  * @property Query|Rotation $rotation
  * @property Query|TimeperiodEntry $timeperiod_entry
  */
 class Timeperiod extends Model
 {
-    public function getTableName()
+    public function getTableName(): string
     {
         return 'timeperiod';
     }
 
-    public function getKeyName()
+    public function getKeyName(): string
     {
         return 'id';
     }
 
-    public function getColumns()
+    public function getColumns(): array
     {
         return [
-            'owned_by_rotation_id'
+            'owned_by_rotation_id',
+            'changed_at',
+            'deleted'
         ];
     }
 
-    public function createRelations(Relations $relations)
+    public function createBehaviors(Behaviors $behaviors): void
+    {
+        $behaviors->add(new MillisecondTimestamp(['changed_at']));
+        $behaviors->add(new BoolCast(['deleted']));
+    }
+
+    public function createRelations(Relations $relations): void
     {
         $relations->belongsTo('rotation', Rotation::class)
             ->setCandidateKey('owned_by_rotation_id')
diff --git a/library/Notifications/Model/TimeperiodEntry.php b/library/Notifications/Model/TimeperiodEntry.php
index 36c262d8..ee8d037e 100644
--- a/library/Notifications/Model/TimeperiodEntry.php
+++ b/library/Notifications/Model/TimeperiodEntry.php
@@ -5,9 +5,11 @@
 namespace Icinga\Module\Notifications\Model;
 
 use DateTime;
+use ipl\Orm\Behavior\BoolCast;
 use ipl\Orm\Behavior\MillisecondTimestamp;
 use ipl\Orm\Behaviors;
 use ipl\Orm\Model;
+use ipl\Orm\Query;
 use ipl\Orm\Relations;
 use Recurr\Frequency;
 use Recurr\Rule;
@@ -24,22 +26,22 @@
  * @property string $timezone
  * @property ?string $rrule
  *
- * @property Timeperiod $timeperiod
- * @property RotationMember $member
+ * @property Query|Timeperiod $timeperiod
+ * @property Query|RotationMember $member
  */
 class TimeperiodEntry extends Model
 {
-    public function getTableName()
+    public function getTableName(): string
     {
         return 'timeperiod_entry';
     }
 
-    public function getKeyName()
+    public function getKeyName(): string
     {
         return 'id';
     }
 
-    public function getColumns()
+    public function getColumns(): array
     {
         return [
             'timeperiod_id',
@@ -48,25 +50,29 @@ public function getColumns()
             'end_time',
             'until_time',
             'timezone',
-            'rrule'
+            'rrule',
+            'changed_at',
+            'deleted'
         ];
     }
 
-    public function getDefaultSort()
+    public function getDefaultSort(): array
     {
         return ['start_time asc', 'end_time asc'];
     }
 
-    public function createBehaviors(Behaviors $behaviors)
+    public function createBehaviors(Behaviors $behaviors): void
     {
         $behaviors->add(new MillisecondTimestamp([
             'start_time',
             'end_time',
-            'until_time'
+            'until_time',
+            'changed_at'
         ]));
+        $behaviors->add(new BoolCast(['deleted']));
     }
 
-    public function createRelations(Relations $relations)
+    public function createRelations(Relations $relations): void
     {
         $relations->belongsTo('timeperiod', Timeperiod::class);
         $relations->belongsTo('member', RotationMember::class);
diff --git a/library/Notifications/Web/Form/ContactForm.php b/library/Notifications/Web/Form/ContactForm.php
index 17121f95..246f015a 100644
--- a/library/Notifications/Web/Form/ContactForm.php
+++ b/library/Notifications/Web/Form/ContactForm.php
@@ -4,11 +4,13 @@
 
 namespace Icinga\Module\Notifications\Web\Form;
 
-use Icinga\Module\Notifications\Common\Database;
+use Icinga\Exception\Http\HttpNotFoundException;
 use Icinga\Module\Notifications\Model\AvailableChannelType;
 use Icinga\Module\Notifications\Model\Channel;
 use Icinga\Module\Notifications\Model\Contact;
-use Icinga\Module\Notifications\Model\ContactAddress;
+use Icinga\Module\Notifications\Model\Rotation;
+use Icinga\Module\Notifications\Model\RotationMember;
+use Icinga\Module\Notifications\Model\RuleEscalationRecipient;
 use Icinga\Web\Session;
 use ipl\Html\Contract\FormSubmitElement;
 use ipl\Html\FormElement\FieldsetElement;
@@ -33,10 +35,9 @@ class ContactForm extends CompatForm
     /** @var ?string Contact ID*/
     private $contactId;
 
-    public function __construct(Connection $db, $contactId = null)
+    public function __construct(Connection $db)
     {
         $this->db = $db;
-        $this->contactId = $contactId;
 
         $this->on(self::ON_SENT, function () {
             if ($this->hasBeenRemoved()) {
@@ -82,7 +83,7 @@ protected function assemble()
         $this->addElement($contact);
 
         $channelOptions = ['' => sprintf(' - %s - ', $this->translate('Please choose'))];
-        $channelOptions += Channel::fetchChannelNames(Database::get());
+        $channelOptions += Channel::fetchChannelNames($this->db);
 
         $contact->addElement(
             'text',
@@ -99,7 +100,8 @@ protected function assemble()
                 'validators' => [
                     new StringLengthValidator(['max' => 254]),
                     new CallbackValidator(function ($value, $validator) {
-                        $contact = Contact::on($this->db)->filter(Filter::equal('username', $value));
+                        $contact = Contact::on($this->db)
+                            ->filter(Filter::equal('username', $value));
                         if ($this->contactId) {
                             $contact->filter(Filter::unequal('id', $this->contactId));
                         }
@@ -157,115 +159,240 @@ protected function assemble()
         }
     }
 
-    public function populate($values)
+    /**
+     * Load the contact with given id
+     *
+     * @param int $id
+     *
+     * @return $this
+     *
+     * @throws HttpNotFoundException
+     */
+    public function loadContact(int $id): self
     {
-        if ($values instanceof Contact) {
-            $formValues = [
-                'contact' => [
-                    'full_name'          => $values->full_name,
-                    'username'           => $values->username,
-                    'default_channel_id' => $values->default_channel_id
-                ]
-            ];
+        $this->contactId = $id;
 
-            foreach ($values->contact_address as $contactInfo) {
-                $formValues['contact_address'][$contactInfo->type] = $contactInfo->address;
-            }
+        $this->populate($this->fetchDbValues());
 
-            $values = $formValues;
-        }
+        return $this;
+    }
 
-        parent::populate($values);
+    /**
+     * Add the new contact
+     */
+    public function addContact(): void
+    {
+        $contactInfo = $this->getValues();
+        $changedAt = time() * 1000;
+        $this->db->beginTransaction();
+        $this->db->insert('contact', $contactInfo['contact'] + ['changed_at' => $changedAt]);
+        $this->contactId = $this->db->lastInsertId();
+
+        foreach (array_filter($contactInfo['contact_address']) as $type => $address) {
+            $address = [
+                'contact_id' => $this->contactId,
+                'type'       => $type,
+                'address'    => $address,
+                'changed_at' => $changedAt
+            ];
 
-        return $this;
+            $this->db->insert('contact_address', $address);
+        }
+
+        $this->db->commitTransaction();
     }
 
     /**
-     * Add or update the contact and its corresponding contact addresses
+     * Edit the contact
      *
      * @return void
      */
-    public function addOrUpdateContact(): void
+    public function editContact(): void
     {
-        $contactInfo = $this->getValues();
+        $this->db->beginTransaction();
 
-        $contact = $contactInfo['contact'];
-        $addressFromForm = $contactInfo['contact_address'];
+        $values = $this->getValues();
+        $storedValues = $this->fetchDbValues();
 
+        $changedAt = time() * 1000;
+        if ($storedValues['contact'] !== $values['contact']) {
+            $this->db->update(
+                'contact',
+                $values['contact'] + ['changed_at' => $changedAt],
+                ['id = ?' => $this->contactId]
+            );
+        }
+
+        $storedAddresses = $storedValues['contact_address_with_id'];
+        foreach ($values['contact_address'] as $type => $address) {
+            if ($address === null) {
+                if (isset($storedAddresses[$type])) {
+                    $this->db->update(
+                        'contact_address',
+                        ['changed_at' => $changedAt, 'deleted' => 'y'],
+                        ['id = ?' => $storedAddresses[$type][0], 'deleted = ?' => 'n']
+                    );
+                }
+            } elseif (! isset($storedAddresses[$type])) {
+                $address = [
+                    'contact_id' => $this->contactId,
+                    'type'       => $type,
+                    'address'    => $address,
+                    'changed_at' => $changedAt
+                ];
+
+                $this->db->insert('contact_address', $address);
+            } elseif ($storedAddresses[$type][1] !== $address) {
+                $this->db->update(
+                    'contact_address',
+                    ['address' => $address, 'changed_at' => $changedAt],
+                    [
+                        'id = ?'         => $storedAddresses[$type][0],
+                        'contact_id = ?' => $this->contactId
+                    ]
+                );
+            }
+        }
+
+        $this->db->commitTransaction();
+    }
+
+    /**
+     * Remove the contact
+     */
+    public function removeContact(): void
+    {
         $this->db->beginTransaction();
 
-        $addressFromDb = [];
-        if ($this->contactId === null) {
-            $this->db->insert('contact', $contact);
-            $this->contactId = $this->db->lastInsertId();
-        } else {
-            $contactFromDb = (array) $this->db->fetchOne(
-                Contact::on($this->db)->withoutColumns(['id'])
-                    ->filter(Filter::equal('id', $this->contactId))
-                    ->assembleSelect()
+        $markAsDeleted = ['changed_at' => time() * 1000, 'deleted' => 'y'];
+        $updateCondition = ['contact_id = ?' => $this->contactId, 'deleted = ?' => 'n'];
+
+        $rotationAndMemberIds = $this->db->fetchPairs(
+            RotationMember::on($this->db)
+                ->columns(['id', 'rotation_id'])
+                ->filter(Filter::equal('contact_id', $this->contactId))
+                ->assembleSelect()
+        );
+
+        $rotationMemberIds = array_keys($rotationAndMemberIds);
+        $rotationIds = array_values($rotationAndMemberIds);
+
+        $this->db->update('rotation_member', $markAsDeleted + ['position' => null], $updateCondition);
+
+        if (! empty($rotationMemberIds)) {
+            $this->db->update(
+                'timeperiod_entry',
+                $markAsDeleted,
+                ['rotation_member_id IN (?)' => $rotationMemberIds, 'deleted = ?' => 'n']
+            );
+        }
+
+        if (! empty($rotationIds)) {
+            $rotationIdsWithOtherMembers = $this->db->fetchCol(
+                RotationMember::on($this->db)
+                    ->columns('rotation_id')
+                    ->filter(
+                        Filter::all(
+                            Filter::equal('rotation_id', $rotationIds),
+                            Filter::unequal('contact_id', $this->contactId)
+                        )
+                    )->assembleSelect()
             );
 
-            if (! empty(array_diff_assoc($contact, $contactFromDb))) {
-                $this->db->update('contact', $contact, ['id = ?' => $this->contactId]);
-            }
+            $toRemoveRotations = array_diff($rotationIds, $rotationIdsWithOtherMembers);
 
-            $addressObjects = (ContactAddress::on($this->db))
-                ->filter(Filter::equal('contact_id', $this->contactId));
+            if (! empty($toRemoveRotations)) {
+                $rotations = Rotation::on($this->db)
+                    ->columns(['id', 'schedule_id', 'priority', 'timeperiod.id'])
+                    ->filter(Filter::equal('id', $toRemoveRotations));
 
-            foreach ($addressObjects as $addressRow) {
-                $addressFromDb[$addressRow->type] = [$addressRow->id, $addressRow->address];
+                /** @var Rotation $rotation */
+                foreach ($rotations as $rotation) {
+                    $rotation->delete();
+                }
             }
         }
 
-        foreach ($addressFromForm as $type => $value) {
-            $this->insertOrUpdateAddress($type, $addressFromForm, $addressFromDb);
+        $escalationIds = $this->db->fetchCol(
+            RuleEscalationRecipient::on($this->db)
+                ->columns('rule_escalation_id')
+                ->filter(Filter::equal('contact_id', $this->contactId))
+                ->assembleSelect()
+        );
+
+        $this->db->update('rule_escalation_recipient', $markAsDeleted, $updateCondition);
+
+        if (! empty($escalationIds)) {
+            $escalationIdsWithOtherRecipients = $this->db->fetchCol(
+                RuleEscalationRecipient::on($this->db)
+                    ->columns('rule_escalation_id')
+                    ->filter(Filter::all(
+                        Filter::equal('rule_escalation_id', $escalationIds),
+                        Filter::unequal('contact_id', $this->contactId)
+                    ))->assembleSelect()
+            );
+
+            $toRemoveEscalations = array_diff($escalationIds, $escalationIdsWithOtherRecipients);
+
+            if (! empty($toRemoveEscalations)) {
+                $this->db->update(
+                    'rule_escalation',
+                    $markAsDeleted + ['position' => null],
+                    ['id IN (?)' => $toRemoveEscalations]
+                );
+            }
         }
 
+        $this->db->update('contactgroup_member', $markAsDeleted, $updateCondition);
+        $this->db->update('contact_address', $markAsDeleted, $updateCondition);
+
+        $this->db->update('contact', $markAsDeleted + ['username' => null], ['id = ?' => $this->contactId]);
+
         $this->db->commitTransaction();
     }
 
-    public function removeContact()
+    /**
+     * Get the contact name
+     *
+     * @return string
+     */
+    public function getContactName(): string
     {
-        $this->db->beginTransaction();
-        $this->db->delete('contactgroup_member', ['contact_id = ?' => $this->contactId]);
-        $this->db->delete('contact_address', ['contact_id = ?' => $this->contactId]);
-        $this->db->delete('contact', ['id = ?' => $this->contactId]);
-        $this->db->commitTransaction();
+        return $this->getElement('contact')->getValue('full_name');
     }
 
     /**
-     * Insert / Update contact address for a given contact
+     * Fetch the values from the database
      *
-     * @param string $type
-     * @param array $addressFromForm
-     * @param array $addressFromDb [id, address] from `contact_adrress` table
+     * @return array
      *
-     * @return void
+     * @throws HttpNotFoundException
      */
-    private function insertOrUpdateAddress(string $type, array $addressFromForm, array $addressFromDb): void
+    private function fetchDbValues(): array
     {
-        if ($addressFromForm[$type] !== null) {
-            if (! isset($addressFromDb[$type])) {
-                $address = [
-                    'contact_id' => $this->contactId,
-                    'type'       => $type,
-                    'address'    => $addressFromForm[$type]
-                ];
+        /** @var ?Contact $contact */
+        $contact = Contact::on($this->db)
+            ->filter(Filter::equal('id', $this->contactId))
+            ->first();
 
-                $this->db->insert('contact_address', $address);
-            } elseif ($addressFromDb[$type][1] !== $addressFromForm[$type]) {
-                $this->db->update(
-                    'contact_address',
-                    ['address' => $addressFromForm[$type]],
-                    [
-                        'id = ?'         => $addressFromDb[$type][0],
-                        'contact_id = ?' => $this->contactId
-                    ]
-                );
-            }
-        } elseif (isset($addressFromDb[$type])) {
-            $this->db->delete('contact_address', ['id = ?' => $addressFromDb[$type][0]]);
+        if ($contact === null) {
+            throw new HttpNotFoundException(t('Contact not found'));
         }
+
+        $values['contact'] =  [
+            'full_name'          => $contact->full_name,
+            'username'           => $contact->username,
+            'default_channel_id' => (string) $contact->default_channel_id
+        ];
+
+        $values['contact_address'] = [];
+        $values['contact_address_with_id'] = []; //TODO: only used in editContact(), find better solution
+        foreach ($contact->contact_address as $contactInfo) {
+            $values['contact_address'][$contactInfo->type] = $contactInfo->address;
+            $values['contact_address_with_id'][$contactInfo->type] = [$contactInfo->id, $contactInfo->address];
+        }
+
+        return $values;
     }
 
     /**
diff --git a/library/Notifications/Widget/CheckboxIcon.php b/library/Notifications/Widget/CheckboxIcon.php
deleted file mode 100644
index 16c5845c..00000000
--- a/library/Notifications/Widget/CheckboxIcon.php
+++ /dev/null
@@ -1,40 +0,0 @@
-<?php
-
-/* Icinga Notifications Web | (c) 2023 Icinga GmbH | GPLv2 */
-
-namespace Icinga\Module\Notifications\Widget;
-
-use Icinga\Module\Notifications\Model\Contact;
-use Icinga\Module\Notifications\Model\RuleEscalationRecipient;
-use ipl\Html\BaseHtmlElement;
-use ipl\Html\Html;
-use ipl\Web\Widget\Icon;
-
-class CheckboxIcon extends BaseHtmlElement
-{
-    /** @var bool Whether the checkbox icon is checked */
-    protected $isChecked;
-
-    protected $tag = 'span';
-
-    protected $defaultAttributes = ['class' => 'checkbox-icon'];
-
-    /**
-     * Create the checkbox icon
-     *
-     * @param bool $isChecked
-     */
-    public function __construct(bool $isChecked = false)
-    {
-        $this->isChecked = $isChecked;
-    }
-
-    protected function assemble()
-    {
-        $this->add(Html::tag('span', ['class' => 'inner-slider']));
-
-        if ($this->isChecked) {
-            $this->addAttributes(['class' => 'checked']);
-        }
-    }
-}
diff --git a/library/Notifications/Widget/ItemList/EventRuleListItem.php b/library/Notifications/Widget/ItemList/EventRuleListItem.php
index cb4127a0..0e8afd14 100644
--- a/library/Notifications/Widget/ItemList/EventRuleListItem.php
+++ b/library/Notifications/Widget/ItemList/EventRuleListItem.php
@@ -6,7 +6,6 @@
 
 use Icinga\Module\Notifications\Common\Links;
 use Icinga\Module\Notifications\Model\Rule;
-use Icinga\Module\Notifications\Widget\CheckboxIcon;
 use Icinga\Module\Notifications\Widget\RuleEscalationRecipientBadge;
 use ipl\Html\BaseHtmlElement;
 use ipl\Html\Html;
@@ -31,11 +30,6 @@ protected function init(): void
             ->set('data-action-item', true);
     }
 
-    protected function assembleVisual(BaseHtmlElement $visual): void
-    {
-        $visual->add(new CheckboxIcon($this->item->is_active === 'y'));
-    }
-
     protected function assembleFooter(BaseHtmlElement $footer): void
     {
         $meta = Html::tag('span', ['class' => 'meta']);
diff --git a/library/Notifications/Widget/RuleEscalationRecipientBadge.php b/library/Notifications/Widget/RuleEscalationRecipientBadge.php
index 698b10b1..ba76c53f 100644
--- a/library/Notifications/Widget/RuleEscalationRecipientBadge.php
+++ b/library/Notifications/Widget/RuleEscalationRecipientBadge.php
@@ -37,6 +37,10 @@ public function __construct(RuleEscalationRecipient $recipient, ?int $moreCount
     public function createBadge()
     {
         $recipientModel = $this->recipient->getRecipient();
+        if ($recipientModel === null) {
+            return;
+        }
+
         $nameColumn = 'name';
         $icon = 'users';
 
diff --git a/public/css/form.less b/public/css/form.less
index ca2a2406..c9626b66 100644
--- a/public/css/form.less
+++ b/public/css/form.less
@@ -108,3 +108,11 @@
 .source-form textarea {
   .monospace-font();
 }
+
+.channel-form {
+  .btn-remove:disabled {
+    background: @gray-light;
+    color: @disabled-gray;
+    border-color: transparent;
+  }
+}