diff --git a/apps/dav/lib/CalDAV/Reminder/INotificationProvider.php b/apps/dav/lib/CalDAV/Reminder/INotificationProvider.php
index 505960ed66208..e8cbfdd0ab368 100644
--- a/apps/dav/lib/CalDAV/Reminder/INotificationProvider.php
+++ b/apps/dav/lib/CalDAV/Reminder/INotificationProvider.php
@@ -42,13 +42,13 @@ interface INotificationProvider {
 	 * Send notification
 	 *
 	 * @param VEvent $vevent
-	 * @param string $calendarDisplayName
+	 * @param string|null $calendarDisplayName
 	 * @param string[] $principalEmailAddresses All email addresses associated to the principal owning the calendar object
 	 * @param IUser[] $users
 	 * @return void
 	 */
 	public function send(VEvent $vevent,
-						 string $calendarDisplayName,
+						 ?string $calendarDisplayName,
 						 array  $principalEmailAddresses,
 						 array $users = []): void;
 }
diff --git a/apps/dav/lib/CalDAV/Reminder/NotificationProvider/AbstractProvider.php b/apps/dav/lib/CalDAV/Reminder/NotificationProvider/AbstractProvider.php
index 6986328facd30..bccbec5fe3caa 100644
--- a/apps/dav/lib/CalDAV/Reminder/NotificationProvider/AbstractProvider.php
+++ b/apps/dav/lib/CalDAV/Reminder/NotificationProvider/AbstractProvider.php
@@ -82,13 +82,13 @@ public function __construct(LoggerInterface $logger,
 	 * Send notification
 	 *
 	 * @param VEvent $vevent
-	 * @param string $calendarDisplayName
+	 * @param string|null $calendarDisplayName
 	 * @param string[] $principalEmailAddresses
 	 * @param IUser[] $users
 	 * @return void
 	 */
 	abstract public function send(VEvent $vevent,
-						   string $calendarDisplayName,
+						   ?string $calendarDisplayName,
 						   array $principalEmailAddresses,
 						   array $users = []): void;
 
@@ -185,4 +185,8 @@ protected function getDTEndFromEvent(VEvent $vevent):Property\ICalendar\DateTime
 
 		return clone $vevent->DTSTART;
 	}
+
+	protected function getCalendarDisplayNameFallback(string $lang): string {
+		return $this->getL10NForLang($lang)->t('Untitled calendar');
+	}
 }
diff --git a/apps/dav/lib/CalDAV/Reminder/NotificationProvider/EmailProvider.php b/apps/dav/lib/CalDAV/Reminder/NotificationProvider/EmailProvider.php
index 3207268896779..da275efdcf19f 100644
--- a/apps/dav/lib/CalDAV/Reminder/NotificationProvider/EmailProvider.php
+++ b/apps/dav/lib/CalDAV/Reminder/NotificationProvider/EmailProvider.php
@@ -70,13 +70,13 @@ public function __construct(IConfig $config,
 	 * Send out notification via email
 	 *
 	 * @param VEvent $vevent
-	 * @param string $calendarDisplayName
+	 * @param string|null $calendarDisplayName
 	 * @param string[] $principalEmailAddresses
 	 * @param array $users
 	 * @throws \Exception
 	 */
 	public function send(VEvent $vevent,
-						 string $calendarDisplayName,
+						 ?string $calendarDisplayName,
 						 array $principalEmailAddresses,
 						 array $users = []):void {
 		$fallbackLanguage = $this->getFallbackLanguage();
@@ -115,7 +115,7 @@ public function send(VEvent $vevent,
 			$template = $this->mailer->createEMailTemplate('dav.calendarReminder');
 			$template->addHeader();
 			$this->addSubjectAndHeading($template, $l10n, $vevent);
-			$this->addBulletList($template, $l10n, $calendarDisplayName, $vevent);
+			$this->addBulletList($template, $l10n, $calendarDisplayName ?? $this->getCalendarDisplayNameFallback($lang), $vevent);
 			$template->addFooter();
 
 			foreach ($emailAddresses as $emailAddress) {
diff --git a/apps/dav/lib/CalDAV/Reminder/NotificationProvider/PushProvider.php b/apps/dav/lib/CalDAV/Reminder/NotificationProvider/PushProvider.php
index 833d74079aa8a..be8bafd2f3569 100644
--- a/apps/dav/lib/CalDAV/Reminder/NotificationProvider/PushProvider.php
+++ b/apps/dav/lib/CalDAV/Reminder/NotificationProvider/PushProvider.php
@@ -73,13 +73,13 @@ public function __construct(IConfig $config,
 	 * Send push notification to all users.
 	 *
 	 * @param VEvent $vevent
-	 * @param string $calendarDisplayName
+	 * @param string|null $calendarDisplayName
 	 * @param string[] $principalEmailAddresses
 	 * @param IUser[] $users
 	 * @throws \Exception
 	 */
 	public function send(VEvent $vevent,
-						 string $calendarDisplayName,
+						 ?string $calendarDisplayName,
 						 array $principalEmailAddresses,
 						 array $users = []):void {
 		if ($this->config->getAppValue('dav', 'sendEventRemindersPush', 'no') !== 'yes') {
@@ -87,7 +87,6 @@ public function send(VEvent $vevent,
 		}
 
 		$eventDetails = $this->extractEventDetails($vevent);
-		$eventDetails['calendar_displayname'] = $calendarDisplayName;
 		$eventUUID = (string) $vevent->UID;
 		if (!$eventUUID) {
 			return;
@@ -95,6 +94,8 @@ public function send(VEvent $vevent,
 		$eventUUIDHash = hash('sha256', $eventUUID, false);
 
 		foreach ($users as $user) {
+			$eventDetails['calendar_displayname'] = $calendarDisplayName ?? $this->getCalendarDisplayNameFallback($this->l10nFactory->getUserLanguage($user));
+
 			/** @var INotification $notification */
 			$notification = $this->manager->createNotification();
 			$notification->setApp(Application::APP_ID)