diff --git a/library/Zend/Log.php b/library/Zend/Log.php
index facd73e..e13021e 100644
--- a/library/Zend/Log.php
+++ b/library/Zend/Log.php
@@ -116,7 +116,7 @@ class Zend_Log
      *
      * @param Zend_Log_Writer_Abstract|null  $writer  default writer
      */
-    public function __construct(Zend_Log_Writer_Abstract $writer = null)
+    public function __construct(?Zend_Log_Writer_Abstract $writer = null)
     {
         $r = new ReflectionClass($this);
         $this->_priorities = array_flip($r->getConstants());