diff --git a/.github/phpstan-baseline.neon b/.github/phpstan-baseline.neon
index 47854e1bb78..10538dd2d56 100644
--- a/.github/phpstan-baseline.neon
+++ b/.github/phpstan-baseline.neon
@@ -35,46 +35,11 @@ parameters:
 			count: 1
 			path: ../app/code/core/Mage/Admin/Model/Config.php
 
-		-
-			message: "#^Parameter \\#1 \\$sourceData of class Varien_Simplexml_Config constructor expects string\\|Varien_Simplexml_Element\\|null, Varien_Simplexml_Config given\\.$#"
-			count: 1
-			path: ../app/code/core/Mage/Admin/Model/Config.php
-
-		-
-			message: "#^Parameter \\#2 \\$arguments of static method Mage\\:\\:getModel\\(\\) expects array\\|object, string given\\.$#"
-			count: 2
-			path: ../app/code/core/Mage/Admin/Model/Config.php
-
-		-
-			message: "#^Parameter \\#2 \\$mergeToObject of method Mage_Core_Model_Config\\:\\:loadModulesConfiguration\\(\\) expects Mage_Core_Model_Config_Base\\|null, Varien_Simplexml_Config given\\.$#"
-			count: 1
-			path: ../app/code/core/Mage/Admin/Model/Config.php
-
-		-
-			message: "#^Parameter \\#2 \\$resource of method Mage_Admin_Model_Config\\:\\:loadAclResources\\(\\) expects Mage_Core_Model_Config_Element\\|null, Varien_Simplexml_Element given\\.$#"
-			count: 1
-			path: ../app/code/core/Mage/Admin/Model/Config.php
-
-		-
-			message: "#^Left side of && is always true\\.$#"
-			count: 1
-			path: ../app/code/core/Mage/Admin/Model/Observer.php
-
 		-
 			message: "#^Cannot call method getClassName\\(\\) on SimpleXMLElement\\|false\\.$#"
 			count: 1
 			path: ../app/code/core/Mage/Admin/Model/Resource/Acl.php
 
-		-
-			message: "#^Parameter \\#2 \\$arguments of static method Mage\\:\\:getModel\\(\\) expects array\\|object, string given\\.$#"
-			count: 2
-			path: ../app/code/core/Mage/Admin/Model/Resource/Acl.php
-
-		-
-			message: "#^Strict comparison using \\=\\=\\= between string and false will always evaluate to false\\.$#"
-			count: 1
-			path: ../app/code/core/Mage/Admin/Model/Resource/Block.php
-
 		-
 			message: "#^Parameter \\#1 \\$role of method Mage_Admin_Model_Resource_Roles\\:\\:_updateRoleUsersAcl\\(\\) expects Mage_Admin_Model_Roles, Mage_Core_Model_Abstract given\\.$#"
 			count: 1
@@ -85,11 +50,6 @@ parameters:
 			count: 1
 			path: ../app/code/core/Mage/Admin/Model/Resource/User.php
 
-		-
-			message: "#^Strict comparison using \\=\\=\\= between string and false will always evaluate to false\\.$#"
-			count: 1
-			path: ../app/code/core/Mage/Admin/Model/Resource/Variable.php
-
 		-
 			message: "#^Call to an undefined method Mage_Admin_Model_Resource_Roles\\:\\:update\\(\\)\\.$#"
 			count: 1
@@ -110,16 +70,6 @@ parameters:
 			count: 1
 			path: ../app/code/core/Mage/Admin/Model/Session.php
 
-		-
-			message: "#^Call to function is_null\\(\\) with bool will always evaluate to false\\.$#"
-			count: 1
-			path: ../app/code/core/Mage/Admin/Model/Session.php
-
-		-
-			message: "#^Parameter \\#1 \\$parent of method Mage_Admin_Model_User\\:\\:findFirstAvailableMenu\\(\\) expects Mage_Core_Model_Config_Element\\|null, Varien_Simplexml_Element given\\.$#"
-			count: 1
-			path: ../app/code/core/Mage/Admin/Model/User.php
-
 		-
 			message: "#^Call to function is_null\\(\\) with Mage_AdminNotification_Model_Inbox will always evaluate to false\\.$#"
 			count: 1
@@ -2305,11 +2255,6 @@ parameters:
 			count: 1
 			path: ../app/code/core/Mage/Api/Model/Acl.php
 
-		-
-			message: "#^Parameter \\#2 \\$arguments of static method Mage\\:\\:getModel\\(\\) expects array\\|object, string given\\.$#"
-			count: 1
-			path: ../app/code/core/Mage/Api/Model/Config.php
-
 		-
 			message: "#^Parameter \\#2 \\$resource of method Mage_Api_Model_Config\\:\\:loadAclResources\\(\\) expects Mage_Core_Model_Config_Element\\|null, Varien_Simplexml_Element given\\.$#"
 			count: 1
@@ -2330,11 +2275,6 @@ parameters:
 			count: 1
 			path: ../app/code/core/Mage/Api/Model/Resource/Acl.php
 
-		-
-			message: "#^Parameter \\#2 \\$arguments of static method Mage\\:\\:getModel\\(\\) expects array\\|object, string given\\.$#"
-			count: 2
-			path: ../app/code/core/Mage/Api/Model/Resource/Acl.php
-
 		-
 			message: "#^Method Mage_Core_Model_Resource_Db_Abstract\\:\\:load\\(\\) invoked with 1 parameter, 2\\-3 required\\.$#"
 			count: 1
@@ -2495,11 +2435,6 @@ parameters:
 			count: 1
 			path: ../app/code/core/Mage/Api/Model/Wsdl/Config.php
 
-		-
-			message: "#^Parameter \\#2 \\$mergeToObject of method Mage_Core_Model_Config\\:\\:loadModulesConfiguration\\(\\) expects Mage_Core_Model_Config_Base\\|null, \\$this\\(Mage_Api_Model_Wsdl_Config\\) given\\.$#"
-			count: 2
-			path: ../app/code/core/Mage/Api/Model/Wsdl/Config.php
-
 		-
 			message: "#^Parameter \\#3 \\$mergeModel of method Mage_Core_Model_Config\\:\\:loadModulesConfiguration\\(\\) expects null, Mage_Api_Model_Wsdl_Config_Base given\\.$#"
 			count: 2
@@ -6900,11 +6835,6 @@ parameters:
 			count: 1
 			path: ../app/code/core/Mage/Core/Helper/Js.php
 
-		-
-			message: "#^Parameter \\#2 \\$mergeToObject of method Mage_Core_Model_Config\\:\\:loadModulesConfiguration\\(\\) expects Mage_Core_Model_Config_Base\\|null, Varien_Simplexml_Config given\\.$#"
-			count: 1
-			path: ../app/code/core/Mage/Core/Helper/Js.php
-
 		-
 			message: "#^Negated boolean expression is always false\\.$#"
 			count: 1
@@ -7060,11 +6990,6 @@ parameters:
 			count: 1
 			path: ../app/code/core/Mage/Core/Model/Cache.php
 
-		-
-			message: "#^Strict comparison using \\=\\=\\= between string and false will always evaluate to false\\.$#"
-			count: 1
-			path: ../app/code/core/Mage/Core/Model/Cache.php
-
 		-
 			message: "#^Call to an undefined method SimpleXMLElement\\:\\:getClassName\\(\\)\\.$#"
 			count: 1
@@ -9190,11 +9115,6 @@ parameters:
 			count: 1
 			path: ../app/code/core/Mage/Eav/Model/Entity/Abstract.php
 
-		-
-			message: "#^Parameter \\#2 \\$arguments of static method Mage\\:\\:getModel\\(\\) expects array\\|object, string given\\.$#"
-			count: 1
-			path: ../app/code/core/Mage/Eav/Model/Entity/Abstract.php
-
 		-
 			message: "#^Property Mage_Eav_Model_Entity_Abstract\\:\\:\\$_read \\(Varien_Db_Adapter_Pdo_Mysql\\) does not accept Varien_Db_Adapter_Interface\\|false\\.$#"
 			count: 1
@@ -9725,11 +9645,6 @@ parameters:
 			count: 1
 			path: ../app/code/core/Mage/ImportExport/Model/Abstract.php
 
-		-
-			message: "#^Parameter \\#2 \\$arguments of static method Mage\\:\\:getModel\\(\\) expects array\\|object, string given\\.$#"
-			count: 1
-			path: ../app/code/core/Mage/ImportExport/Model/Abstract.php
-
 		-
 			message: "#^If condition is always true\\.$#"
 			count: 1
@@ -9865,11 +9780,6 @@ parameters:
 			count: 1
 			path: ../app/code/core/Mage/ImportExport/Model/Import.php
 
-		-
-			message: "#^Parameter \\#2 \\$arguments of static method Mage\\:\\:getModel\\(\\) expects array\\|object, string given\\.$#"
-			count: 3
-			path: ../app/code/core/Mage/ImportExport/Model/Import.php
-
 		-
 			message: "#^Property Mage_ImportExport_Model_Import\\:\\:\\$_entityAdapter \\(Mage_ImportExport_Model_Import_Entity_Abstract\\) does not accept Mage_Core_Model_Abstract\\|false\\.$#"
 			count: 1
@@ -10235,11 +10145,6 @@ parameters:
 			count: 1
 			path: ../app/code/core/Mage/Install/Model/Config.php
 
-		-
-			message: "#^Parameter \\#2 \\$mergeToObject of method Mage_Core_Model_Config\\:\\:loadModulesConfiguration\\(\\) expects Mage_Core_Model_Config_Base\\|null, \\$this\\(Mage_Install_Model_Config\\) given\\.$#"
-			count: 1
-			path: ../app/code/core/Mage/Install/Model/Config.php
-
 		-
 			message: "#^Call to function is_null\\(\\) with Mage_Install_Model_Session will always evaluate to false\\.$#"
 			count: 1
@@ -10850,11 +10755,6 @@ parameters:
 			count: 1
 			path: ../app/code/core/Mage/Payment/Model/Method/Abstract.php
 
-		-
-			message: "#^Parameter \\#2 \\$arguments of static method Mage\\:\\:getModel\\(\\) expects array\\|object, string given\\.$#"
-			count: 1
-			path: ../app/code/core/Mage/Payment/Model/Method/Abstract.php
-
 		-
 			message: "#^Binary operation \"\\*\\=\" between string and 2 results in an error\\.$#"
 			count: 1
@@ -11040,11 +10940,6 @@ parameters:
 			count: 1
 			path: ../app/code/core/Mage/Paypal/Model/Api/Abstract.php
 
-		-
-			message: "#^Parameter \\#2 \\$arguments of static method Mage\\:\\:getModel\\(\\) expects array\\|object, string given\\.$#"
-			count: 1
-			path: ../app/code/core/Mage/Paypal/Model/Api/Abstract.php
-
 		-
 			message: "#^Call to an undefined method Mage_Paypal_Model_Api_Nvp\\:\\:_export\\(\\)\\.$#"
 			count: 1
@@ -11190,11 +11085,6 @@ parameters:
 			count: 1
 			path: ../app/code/core/Mage/Paypal/Model/Express/Checkout.php
 
-		-
-			message: "#^Parameter \\#2 \\$arguments of static method Mage\\:\\:getModel\\(\\) expects array\\|object, string given\\.$#"
-			count: 1
-			path: ../app/code/core/Mage/Paypal/Model/Express/Checkout.php
-
 		-
 			message: "#^Parameter \\#3 \\$storeId of method Mage_Customer_Model_Customer\\:\\:sendNewAccountEmail\\(\\) expects string, int given\\.$#"
 			count: 2
@@ -11245,11 +11135,6 @@ parameters:
 			count: 1
 			path: ../app/code/core/Mage/Paypal/Model/Ipn.php
 
-		-
-			message: "#^Parameter \\#2 \\$arguments of static method Mage\\:\\:getModel\\(\\) expects array\\|object, string given\\.$#"
-			count: 1
-			path: ../app/code/core/Mage/Paypal/Model/Ipn.php
-
 		-
 			message: "#^Parameter \\#2 \\$url of method Zend_Http_Client_Adapter_Interface\\:\\:write\\(\\) expects Zend_Uri_Http, string given\\.$#"
 			count: 1
@@ -14375,11 +14260,6 @@ parameters:
 			count: 1
 			path: ../app/code/core/Mage/Shipping/Model/Carrier/Abstract.php
 
-		-
-			message: "#^Parameter \\#2 \\$arguments of static method Mage\\:\\:getModel\\(\\) expects array\\|object, string given\\.$#"
-			count: 1
-			path: ../app/code/core/Mage/Shipping/Model/Carrier/Abstract.php
-
 		-
 			message: "#^Property Mage_Shipping_Model_Carrier_Abstract\\:\\:\\$_numBoxes \\(int\\) does not accept float\\.$#"
 			count: 1
@@ -15070,11 +14950,6 @@ parameters:
 			count: 1
 			path: ../app/code/core/Mage/Widget/Model/Resource/Widget/Instance.php
 
-		-
-			message: "#^Parameter \\#2 \\$mergeToObject of method Mage_Core_Model_Config\\:\\:loadModulesConfiguration\\(\\) expects Mage_Core_Model_Config_Base\\|null, Varien_Simplexml_Config given\\.$#"
-			count: 1
-			path: ../app/code/core/Mage/Widget/Model/Widget.php
-
 		-
 			message: "#^Comparison operation \"\\>\\=\" between int\\<0, max\\>\\|false and 0 is always true\\.$#"
 			count: 1
diff --git a/app/Mage.php b/app/Mage.php
index 4c4f8a607ef..2c5d36e1994 100644
--- a/app/Mage.php
+++ b/app/Mage.php
@@ -508,7 +508,7 @@ public static function dispatchEvent($name, array $data = [])
      *
      * @link    Mage_Core_Model_Config::getModelInstance
      * @param   string $modelClass
-     * @param   array|object $arguments
+     * @param   array|string|object $arguments
      * @return  Mage_Core_Model_Abstract|false
      */
     public static function getModel($modelClass = '', $arguments = [])
diff --git a/app/code/core/Mage/Admin/Model/Config.php b/app/code/core/Mage/Admin/Model/Config.php
index 35bc407bfbf..f8549e41174 100644
--- a/app/code/core/Mage/Admin/Model/Config.php
+++ b/app/code/core/Mage/Admin/Model/Config.php
@@ -43,7 +43,6 @@ public function __construct()
         parent::__construct();
         $this->setCacheId('adminhtml_acl_menu_config');
 
-        /** @var Varien_Simplexml_Config $adminhtmlConfig */
         $adminhtmlConfig = Mage::app()->loadCache($this->getCacheId());
         if ($adminhtmlConfig) {
             $this->_adminhtmlConfig = new Varien_Simplexml_Config($adminhtmlConfig);
@@ -80,7 +79,7 @@ public function __construct()
      * Load Acl resources from config
      *
      * @param Mage_Admin_Model_Acl $acl
-     * @param Mage_Core_Model_Config_Element $resource
+     * @param Mage_Core_Model_Config_Element|Varien_Simplexml_Element $resource
      * @param string $parentName
      * @return $this
      */
diff --git a/app/code/core/Mage/Admin/Model/Observer.php b/app/code/core/Mage/Admin/Model/Observer.php
index f98f45333ae..d697fb194de 100644
--- a/app/code/core/Mage/Admin/Model/Observer.php
+++ b/app/code/core/Mage/Admin/Model/Observer.php
@@ -70,7 +70,7 @@ public function actionPreDispatchAdmin($observer)
                         $session->login($username, $password, $request);
                         $request->setPost('login', null);
                     } else {
-                        if ($request && !$request->getParam('messageSent')) {
+                        if (!$request->getParam('messageSent')) {
                             Mage::getSingleton('adminhtml/session')->addError(
                                 Mage::helper('adminhtml')->__('Invalid Form Key. Please refresh the page.')
                             );
diff --git a/app/code/core/Mage/Admin/Model/Session.php b/app/code/core/Mage/Admin/Model/Session.php
index 76d287627c5..cba417c24ad 100644
--- a/app/code/core/Mage/Admin/Model/Session.php
+++ b/app/code/core/Mage/Admin/Model/Session.php
@@ -63,7 +63,7 @@ class Mage_Admin_Model_Session extends Mage_Core_Model_Session_Abstract
     /**
      * Whether it is the first page after successfull login
      *
-     * @var bool
+     * @var bool|null
      */
     protected $_isFirstPageAfterLogin;
 
diff --git a/app/code/core/Mage/Admin/Model/User.php b/app/code/core/Mage/Admin/Model/User.php
index c2bedf1c450..de9520a0582 100644
--- a/app/code/core/Mage/Admin/Model/User.php
+++ b/app/code/core/Mage/Admin/Model/User.php
@@ -504,7 +504,7 @@ protected function _getHelper($helperName)
     /**
      * Find first menu item that user is able to access
      *
-     * @param Mage_Core_Model_Config_Element $parent
+     * @param Mage_Core_Model_Config_Element|Varien_Simplexml_Element $parent
      * @param string $path
      * @param int $level
      * @return string
diff --git a/app/code/core/Mage/AdminNotification/Model/Feed.php b/app/code/core/Mage/AdminNotification/Model/Feed.php
index 6f5d8e84cae..6260412f5ed 100644
--- a/app/code/core/Mage/AdminNotification/Model/Feed.php
+++ b/app/code/core/Mage/AdminNotification/Model/Feed.php
@@ -120,7 +120,7 @@ public function getFrequency()
     /**
      * Retrieve Last update time
      *
-     * @return int
+     * @return string|false
      */
     public function getLastUpdate()
     {
diff --git a/app/code/core/Mage/Core/Model/App.php b/app/code/core/Mage/Core/Model/App.php
index bd0a8b91c33..7c8251ffeda 100644
--- a/app/code/core/Mage/Core/Model/App.php
+++ b/app/code/core/Mage/Core/Model/App.php
@@ -1165,7 +1165,7 @@ public function getCache()
      * Loading cache data
      *
      * @param   string $id
-     * @return  mixed
+     * @return  string|false
      */
     public function loadCache($id)
     {
diff --git a/app/code/core/Mage/Core/Model/Cache.php b/app/code/core/Mage/Core/Model/Cache.php
index 695453c78a2..43f56c6ea73 100644
--- a/app/code/core/Mage/Core/Model/Cache.php
+++ b/app/code/core/Mage/Core/Model/Cache.php
@@ -366,7 +366,7 @@ public function getFrontend()
      * Load data from cache by id
      *
      * @param   string $id
-     * @return  string
+     * @return  string|false
      */
     public function load($id)
     {
diff --git a/app/code/core/Mage/Core/Model/Config.php b/app/code/core/Mage/Core/Model/Config.php
index 87fa1981bc6..f98dd818c12 100644
--- a/app/code/core/Mage/Core/Model/Config.php
+++ b/app/code/core/Mage/Core/Model/Config.php
@@ -1013,9 +1013,9 @@ public function determineOmittedNamespace($name, $asFullModuleName = false)
      * specidied xml file name to one object
      *
      * @param string $fileName
-     * @param null|Mage_Core_Model_Config_Base $mergeToObject
+     * @param null|Mage_Core_Model_Config_Base|Varien_Simplexml_Config $mergeToObject
      * @param null $mergeModel
-     * @return Mage_Core_Model_Config_Base
+     * @return Mage_Core_Model_Config_Base|Varien_Simplexml_Config
      */
     public function loadModulesConfiguration($fileName, $mergeToObject = null, $mergeModel = null)
     {
diff --git a/app/code/core/Mage/Log/Model/Visitor/Online.php b/app/code/core/Mage/Log/Model/Visitor/Online.php
index 2d7aeab0242..2d19ff23522 100644
--- a/app/code/core/Mage/Log/Model/Visitor/Online.php
+++ b/app/code/core/Mage/Log/Model/Visitor/Online.php
@@ -66,7 +66,7 @@ public function prepare()
     /**
      * Retrieve last prepare at timestamp
      *
-     * @return int
+     * @return string|false
      */
     public function getPrepareAt()
     {
diff --git a/lib/Varien/Cache/Core.php b/lib/Varien/Cache/Core.php
index ddaaa298df2..c75775c2e68 100644
--- a/lib/Varien/Cache/Core.php
+++ b/lib/Varien/Cache/Core.php
@@ -155,7 +155,7 @@ public function load($id, $doNotTestCacheValidity = false, $doNotUnserialize = f
             // Seems we've got chunked data
 
             $arr = explode('|', $data);
-            $chunks = isset($arr[1]) ? $arr[1] : false;
+            $chunks = $arr[1] ?? false;
             $chunkData = [];
 
             if ($chunks && is_numeric($chunks)) {