diff --git a/lib/Doctrine/Deprecations/Deprecation.php b/lib/Doctrine/Deprecations/Deprecation.php
index dc29820..a583057 100644
--- a/lib/Doctrine/Deprecations/Deprecation.php
+++ b/lib/Doctrine/Deprecations/Deprecation.php
@@ -8,6 +8,7 @@
 
 use function array_key_exists;
 use function array_reduce;
+use function assert;
 use function debug_backtrace;
 use function sprintf;
 use function strpos;
@@ -175,6 +176,8 @@ private static function delegateTriggerToBackend(string $message, array $backtra
                 'link' => $link,
             ];
 
+            assert(self::$logger !== null);
+
             self::$logger->notice($message, $context);
         }
 
diff --git a/psalm.xml b/psalm.xml
index 0d1301f..fe4301e 100644
--- a/psalm.xml
+++ b/psalm.xml
@@ -1,6 +1,6 @@
 <?xml version="1.0"?>
 <psalm
-    errorLevel="4"
+    errorLevel="3"
     resolveFromConfigFile="true"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xmlns="https://getpsalm.org/schema/config"