diff --git a/lib/private/User/Manager.php b/lib/private/User/Manager.php
index 303050a771..eceeed2050 100644
--- a/lib/private/User/Manager.php
+++ b/lib/private/User/Manager.php
@@ -547,6 +547,7 @@ class Manager extends PublicEmitter implements IUserManager {
 
 	/**
 	 * @param \Closure $callback
+	 * @psalm-param \Closure(\OCP\IUser):?bool $callback
 	 * @since 11.0.0
 	 */
 	public function callForSeenUsers(\Closure $callback) {
diff --git a/lib/public/IUserManager.php b/lib/public/IUserManager.php
index baa37af8d5..e8a7fc7827 100644
--- a/lib/public/IUserManager.php
+++ b/lib/public/IUserManager.php
@@ -179,6 +179,7 @@ interface IUserManager {
 
 	/**
 	 * @param \Closure $callback
+	 * @psalm-param \Closure(\OCP\IUser):?bool $callback
 	 * @since 11.0.0
 	 */
 	public function callForSeenUsers(\Closure $callback);