diff --git a/php/src/Docker/DockerActionManager.php b/php/src/Docker/DockerActionManager.php
index 812d93ca..6df3e635 100644
--- a/php/src/Docker/DockerActionManager.php
+++ b/php/src/Docker/DockerActionManager.php
@@ -431,6 +431,9 @@ class DockerActionManager
             $tagArray = explode(':', $output['Config']['Image']);
             $tag = $tagArray[1];
             apcu_add($cacheKey, $tag);
+            /**
+             * @psalm-suppress TypeDoesNotContainNull
+             */
             if ($tag === null) {
                 error_log("No tag was found when getting the current channel. You probably did not follow the documentation correctly. Changing the channel to the default 'latest'.");
                 $tag = 'latest';