diff --git a/lib/Controller/EpisodeActionController.php b/lib/Controller/EpisodeActionController.php
index 8f17220..ce92782 100644
--- a/lib/Controller/EpisodeActionController.php
+++ b/lib/Controller/EpisodeActionController.php
@@ -98,7 +98,7 @@ class EpisodeActionController extends Controller {
 	 * @return DateTime
 	 */
 	private function createDateTimeFromTimestamp(?int $since): DateTime {
-		return ($since)
+		return ($since !== null)
 			? (new \DateTime)->setTimestamp($since)
 			: (new \DateTime('-1 week'));
 	}
diff --git a/lib/Controller/SubscriptionChangeController.php b/lib/Controller/SubscriptionChangeController.php
index 6be166f..6d4b38e 100644
--- a/lib/Controller/SubscriptionChangeController.php
+++ b/lib/Controller/SubscriptionChangeController.php
@@ -73,7 +73,7 @@ class SubscriptionChangeController extends Controller {
 	 * @return DateTime
 	 */
 	private function createDateTimeFromTimestamp(?int $since): DateTime {
-		return ($since)
+		return ($since !== null)
 			? (new \DateTime)->setTimestamp($since)
 			: (new \DateTime('-1 week'));
 	}