3 files changed, 3 insertions, 3 deletions
diff --git a/apps/dav/lib/CalDAV/Activity/Provider/Calendar.php b/apps/dav/lib/CalDAV/Activity/Provider/Calendar.php
index daab7806e46..e4cc5fadf7c 100644
--- a/apps/dav/lib/CalDAV/Activity/Provider/Calendar.php
+++ b/apps/dav/lib/CalDAV/Activity/Provider/Calendar.php
@@ -83,7 +83,7 @@ class Calendar extends Base {
 	 * @throws \InvalidArgumentException
 	 * @since 11.0.0
 	 */
-	public function parse($language, IEvent $event, IEvent $previousEvent = null) {
+	public function parse($language, IEvent $event, ?IEvent $previousEvent = null) {
 		if ($event->getApp() !== 'dav' || $event->getType() !== 'calendar') {
 			throw new \InvalidArgumentException();
 		}
diff --git a/apps/dav/lib/CalDAV/Activity/Provider/Event.php b/apps/dav/lib/CalDAV/Activity/Provider/Event.php
index 13f0036b0b0..4dcb18fdb90 100644
--- a/apps/dav/lib/CalDAV/Activity/Provider/Event.php
+++ b/apps/dav/lib/CalDAV/Activity/Provider/Event.php
@@ -121,7 +121,7 @@ class Event extends Base {
 	 * @throws \InvalidArgumentException
 	 * @since 11.0.0
 	 */
-	public function parse($language, IEvent $event, IEvent $previousEvent = null) {
+	public function parse($language, IEvent $event, ?IEvent $previousEvent = null) {
 		if ($event->getApp() !== 'dav' || $event->getType() !== 'calendar_event') {
 			throw new \InvalidArgumentException();
 		}
diff --git a/apps/dav/lib/CalDAV/Activity/Provider/Todo.php b/apps/dav/lib/CalDAV/Activity/Provider/Todo.php
index e2ddb99a1af..0a8434b9595 100644
--- a/apps/dav/lib/CalDAV/Activity/Provider/Todo.php
+++ b/apps/dav/lib/CalDAV/Activity/Provider/Todo.php
@@ -36,7 +36,7 @@ class Todo extends Event {
 	 * @throws \InvalidArgumentException
 	 * @since 11.0.0
 	 */
-	public function parse($language, IEvent $event, IEvent $previousEvent = null) {
+	public function parse($language, IEvent $event, ?IEvent $previousEvent = null) {
 		if ($event->getApp() !== 'dav' || $event->getType() !== 'calendar_todo') {
 			throw new \InvalidArgumentException();
 		}