diff --git a/apps/dav/lib/CalDAV/Activity/Provider/Calendar.php b/apps/dav/lib/CalDAV/Activity/Provider/Calendar.php
index 6082e68dcd2a8..36d425ecf63aa 100644
--- a/apps/dav/lib/CalDAV/Activity/Provider/Calendar.php
+++ b/apps/dav/lib/CalDAV/Activity/Provider/Calendar.php
@@ -168,32 +168,32 @@ protected function getParameters(IEvent $event) {
 			case self::SUBJECT_UNSHARE_USER . '_self':
 				return [
 					'actor' => $this->generateUserParameter($parameters[0]),
-					'calendar' => $this->generateCalendarParameter($event->getObjectId(), $parameters[1]),
+					'calendar' => $this->generateCalendarParameter((int)$event->getObjectId(), $parameters[1]),
 				];
 			case self::SUBJECT_SHARE_USER . '_you':
 			case self::SUBJECT_UNSHARE_USER . '_you':
 				return [
 					'user' => $this->generateUserParameter($parameters[0]),
-					'calendar' => $this->generateCalendarParameter($event->getObjectId(), $parameters[1]),
+					'calendar' => $this->generateCalendarParameter((int)$event->getObjectId(), $parameters[1]),
 				];
 			case self::SUBJECT_SHARE_USER . '_by':
 			case self::SUBJECT_UNSHARE_USER . '_by':
 				return [
 					'user' => $this->generateUserParameter($parameters[0]),
-					'calendar' => $this->generateCalendarParameter($event->getObjectId(), $parameters[1]),
+					'calendar' => $this->generateCalendarParameter((int)$event->getObjectId(), $parameters[1]),
 					'actor' => $this->generateUserParameter($parameters[2]),
 				];
 			case self::SUBJECT_SHARE_GROUP . '_you':
 			case self::SUBJECT_UNSHARE_GROUP . '_you':
 				return [
 					'group' => $this->generateGroupParameter($parameters[0]),
-					'calendar' => $this->generateCalendarParameter($event->getObjectId(), $parameters[1]),
+					'calendar' => $this->generateCalendarParameter((int)$event->getObjectId(), $parameters[1]),
 				];
 			case self::SUBJECT_SHARE_GROUP . '_by':
 			case self::SUBJECT_UNSHARE_GROUP . '_by':
 				return [
 					'group' => $this->generateGroupParameter($parameters[0]),
-					'calendar' => $this->generateCalendarParameter($event->getObjectId(), $parameters[1]),
+					'calendar' => $this->generateCalendarParameter((int)$event->getObjectId(), $parameters[1]),
 					'actor' => $this->generateUserParameter($parameters[2]),
 				];
 		}
diff --git a/apps/dav/lib/CalDAV/Activity/Provider/Event.php b/apps/dav/lib/CalDAV/Activity/Provider/Event.php
index b591eaa351c9a..2c2e3d01c28a7 100644
--- a/apps/dav/lib/CalDAV/Activity/Provider/Event.php
+++ b/apps/dav/lib/CalDAV/Activity/Provider/Event.php
@@ -124,14 +124,14 @@ protected function getParameters(IEvent $event) {
 			case self::SUBJECT_OBJECT_UPDATE . '_event':
 				return [
 					'actor' => $this->generateUserParameter($parameters[0]),
-					'calendar' => $this->generateCalendarParameter($event->getObjectId(), $parameters[1]),
+					'calendar' => $this->generateCalendarParameter((int)$event->getObjectId(), $parameters[1]),
 					'event' => $this->generateObjectParameter($parameters[2]),
 				];
 			case self::SUBJECT_OBJECT_ADD . '_event_self':
 			case self::SUBJECT_OBJECT_DELETE . '_event_self':
 			case self::SUBJECT_OBJECT_UPDATE . '_event_self':
 				return [
-					'calendar' => $this->generateCalendarParameter($event->getObjectId(), $parameters[1]),
+					'calendar' => $this->generateCalendarParameter((int)$event->getObjectId(), $parameters[1]),
 					'event' => $this->generateObjectParameter($parameters[2]),
 				];
 		}
diff --git a/apps/dav/lib/CalDAV/Activity/Provider/Todo.php b/apps/dav/lib/CalDAV/Activity/Provider/Todo.php
index 0ad1d137455c1..a665caa0e6a61 100644
--- a/apps/dav/lib/CalDAV/Activity/Provider/Todo.php
+++ b/apps/dav/lib/CalDAV/Activity/Provider/Todo.php
@@ -95,7 +95,7 @@ protected function getParameters(IEvent $event) {
 			case self::SUBJECT_OBJECT_UPDATE . '_todo_needs_action':
 				return [
 					'actor' => $this->generateUserParameter($parameters[0]),
-					'calendar' => $this->generateCalendarParameter($event->getObjectId(), $parameters[1]),
+					'calendar' => $this->generateCalendarParameter((int)$event->getObjectId(), $parameters[1]),
 					'todo' => $this->generateObjectParameter($parameters[2]),
 				];
 			case self::SUBJECT_OBJECT_ADD . '_todo_self':
@@ -104,7 +104,7 @@ protected function getParameters(IEvent $event) {
 			case self::SUBJECT_OBJECT_UPDATE . '_todo_completed_self':
 			case self::SUBJECT_OBJECT_UPDATE . '_todo_needs_action_self':
 				return [
-					'calendar' => $this->generateCalendarParameter($event->getObjectId(), $parameters[1]),
+					'calendar' => $this->generateCalendarParameter((int)$event->getObjectId(), $parameters[1]),
 					'todo' => $this->generateObjectParameter($parameters[2]),
 				];
 		}
diff --git a/apps/dav/lib/CalDAV/BirthdayService.php b/apps/dav/lib/CalDAV/BirthdayService.php
index 702b74bf1b376..e11f922a63688 100644
--- a/apps/dav/lib/CalDAV/BirthdayService.php
+++ b/apps/dav/lib/CalDAV/BirthdayService.php
@@ -270,7 +270,7 @@ protected function getAllAffectedPrincipals($addressBookId) {
 	 * @param string  $cardData
 	 * @param array $book
 	 * @param int $calendarId
-	 * @param string $type
+	 * @param string[] $type
 	 */
 	private function updateCalendar($cardUri, $cardData, $book, $calendarId, $type) {
 		$objectUri = $book['uri'] . '-' . $cardUri . $type['postfix'] . '.ics';
diff --git a/apps/dav/lib/CalDAV/CalDavBackend.php b/apps/dav/lib/CalDAV/CalDavBackend.php
index 1cf27a800252c..b85415e28fc6e 100644
--- a/apps/dav/lib/CalDAV/CalDavBackend.php
+++ b/apps/dav/lib/CalDAV/CalDavBackend.php
@@ -50,6 +50,7 @@
 use Sabre\VObject\DateTimeParser;
 use Sabre\VObject\Reader;
 use Sabre\VObject\Recur\EventIterator;
+use Sabre\Uri;
 use Symfony\Component\EventDispatcher\EventDispatcherInterface;
 use Symfony\Component\EventDispatcher\GenericEvent;
 
@@ -318,7 +319,7 @@ function getCalendarsForUser($principalUri) {
 				}
 			}
 
-			list(, $name) = URLUtil::splitPath($row['principaluri']);
+			list(, $name) = Uri\split($row['principaluri']);
 			$uri = $row['uri'] . '_shared_by_' . $name;
 			$row['displayname'] = $row['displayname'] . ' (' . $this->getUserDisplayName($name) . ')';
 			$components = [];
@@ -432,7 +433,7 @@ public function getPublicCalendars() {
 			->execute();
 
 		while($row = $result->fetch()) {
-			list(, $name) = URLUtil::splitPath($row['principaluri']);
+			list(, $name) = Uri\split($row['principaluri']);
 			$row['displayname'] = $row['displayname'] . "($name)";
 			$components = [];
 			if ($row['components']) {
@@ -498,7 +499,7 @@ public function getPublicCalendar($uri) {
 			throw new NotFound('Node with name \'' . $uri . '\' could not be found');
 		}
 
-		list(, $name) = URLUtil::splitPath($row['principaluri']);
+		list(, $name) = Uri\split($row['principaluri']);
 		$row['displayname'] = $row['displayname'] . ' ' . "($name)";
 		$components = [];
 		if ($row['components']) {
@@ -2104,7 +2105,7 @@ protected function getCalendarObjectId($calendarId, $uri) {
 
 	private function convertPrincipal($principalUri, $toV2) {
 		if ($this->principalBackend->getPrincipalPrefix() === 'principals') {
-			list(, $name) = URLUtil::splitPath($principalUri);
+			list(, $name) = Uri\split($principalUri);
 			if ($toV2 === true) {
 				return "principals/users/$name";
 			}