diff --git a/extensions/mentions/src/Formatter/UnparsePostMentions.php b/extensions/mentions/src/Formatter/UnparsePostMentions.php
index e7866deab4..3cfbfa0558 100644
--- a/extensions/mentions/src/Formatter/UnparsePostMentions.php
+++ b/extensions/mentions/src/Formatter/UnparsePostMentions.php
@@ -28,7 +28,7 @@ public function __construct(TranslatorInterface $translator)
     /**
      * Configure rendering for user mentions.
      *
-     * @param string $xml
+     * @param string|null $xml
      * @param mixed $context
      * @return mixed $xml to be unparsed
      */
diff --git a/extensions/mentions/src/Formatter/UnparseTagMentions.php b/extensions/mentions/src/Formatter/UnparseTagMentions.php
index c4d98debaf..ff3ccf8342 100644
--- a/extensions/mentions/src/Formatter/UnparseTagMentions.php
+++ b/extensions/mentions/src/Formatter/UnparseTagMentions.php
@@ -18,7 +18,7 @@ class UnparseTagMentions
     /**
      * Configure rendering for user mentions.
      *
-     * @param string $xml
+     * @param string|null $xml
      * @param mixed $context
      * @return mixed $xml to be unparsed
      */
diff --git a/extensions/mentions/src/Formatter/UnparseUserMentions.php b/extensions/mentions/src/Formatter/UnparseUserMentions.php
index cdba49b76a..f42c7bac39 100644
--- a/extensions/mentions/src/Formatter/UnparseUserMentions.php
+++ b/extensions/mentions/src/Formatter/UnparseUserMentions.php
@@ -29,7 +29,7 @@ public function __construct(TranslatorInterface $translator)
     /**
      * Configure rendering for user mentions.
      *
-     * @param string $xml
+     * @param string|null $xml
      * @param mixed $context
      * @return mixed $xml to be unparsed
      */