diff --git a/app/code/core/Mage/Captcha/Model/Zend.php b/app/code/core/Mage/Captcha/Model/Zend.php
index 1da978abf2d..c7142e783a6 100644
--- a/app/code/core/Mage/Captcha/Model/Zend.php
+++ b/app/code/core/Mage/Captcha/Model/Zend.php
@@ -64,7 +64,7 @@ class Mage_Captcha_Model_Zend extends Zend_Captcha_Image implements Mage_Captcha
     /**
      * Generated word
      *
-     * @var string|null
+     * @var string
      */
     protected $_word;
 
@@ -483,7 +483,7 @@ protected function _setWord($word)
     protected function _clearWord()
     {
         $this->getSession()->unsetData($this->_getFormIdKey(self::SESSION_WORD));
-        $this->_word = null;
+        $this->_word = '';
         return $this;
     }
 
diff --git a/app/code/core/Mage/Eav/Model/Adminhtml/System/Config/Source/Inputtype/Validator.php b/app/code/core/Mage/Eav/Model/Adminhtml/System/Config/Source/Inputtype/Validator.php
index 842d962c88c..55f5257bf79 100644
--- a/app/code/core/Mage/Eav/Model/Adminhtml/System/Config/Source/Inputtype/Validator.php
+++ b/app/code/core/Mage/Eav/Model/Adminhtml/System/Config/Source/Inputtype/Validator.php
@@ -22,7 +22,7 @@
 class Mage_Eav_Model_Adminhtml_System_Config_Source_Inputtype_Validator extends Zend_Validate_InArray
 {
     /**
-     * @var array<string, string>|null
+     * @inheritdoc
      */
     protected $_messageTemplates;
 
@@ -34,7 +34,7 @@ public function __construct()
         $haystack = $helper->getInputTypesValidatorData();
 
         //reset message template and set custom
-        $this->_messageTemplates = null;
+        $this->_messageTemplates = [];
         $this->_initMessageTemplates();
 
         //parent construct with options
diff --git a/dev/phpstan/stubs/Zend_Captcha_Word.stub b/dev/phpstan/stubs/Zend_Captcha_Word.stub
deleted file mode 100644
index b1b60b63f70..00000000000
--- a/dev/phpstan/stubs/Zend_Captcha_Word.stub
+++ /dev/null
@@ -1,11 +0,0 @@
-<?php
-
-abstract class Zend_Captcha_Word
-{
-    /**
-     * Generated word
-     *
-     * @var string|null
-     */
-    protected $_word;
-}
diff --git a/dev/phpstan/stubs/Zend_Validate_InArray.stub b/dev/phpstan/stubs/Zend_Validate_InArray.stub
deleted file mode 100644
index dcb28e0a281..00000000000
--- a/dev/phpstan/stubs/Zend_Validate_InArray.stub
+++ /dev/null
@@ -1,9 +0,0 @@
-<?php
-
-class Zend_Validate_InArray
-{
-    /**
-     * @var array<string, string>|null
-     */
-    protected $_messageTemplates;
-}
diff --git a/phpstan.dist.neon b/phpstan.dist.neon
index 5bb1048fdfd..eb99f86b075 100644
--- a/phpstan.dist.neon
+++ b/phpstan.dist.neon
@@ -71,9 +71,6 @@ parameters:
 
         # Instantiated class not found
         - lib/Varien/Image/Adapter.php
-    stubFiles:
-        - dev/phpstan/stubs/Zend_Captcha_Word.stub
-        - dev/phpstan/stubs/Zend_Validate_InArray.stub
     level: 4
     checkFunctionNameCase: true
     checkInternalClassCaseSensitivity: true