diff --git a/composer.lock b/composer.lock
index 0d4bad7ee..26e721b4b 100644
--- a/composer.lock
+++ b/composer.lock
@@ -1844,12 +1844,12 @@
             "source": {
                 "type": "git",
                 "url": "https://github.com/rockettheme/toolbox.git",
-                "reference": "3e6e698423d86415a329b284fa251a588b1494ac"
+                "reference": "125d72f87f772806aeafc3ddc136fc42662857a0"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/rockettheme/toolbox/zipball/3e6e698423d86415a329b284fa251a588b1494ac",
-                "reference": "3e6e698423d86415a329b284fa251a588b1494ac",
+                "url": "https://api.github.com/repos/rockettheme/toolbox/zipball/125d72f87f772806aeafc3ddc136fc42662857a0",
+                "reference": "125d72f87f772806aeafc3ddc136fc42662857a0",
                 "shasum": ""
             },
             "archive": {
@@ -1907,7 +1907,7 @@
                 "source": "https://github.com/rockettheme/toolbox/tree/develop",
                 "issues": "https://github.com/rockettheme/toolbox/issues"
             },
-            "time": "2020-01-23T20:26:01+00:00"
+            "time": "2020-02-03T08:53:52+00:00"
         },
         {
             "name": "seld/cli-prompt",
@@ -1959,16 +1959,16 @@
         },
         {
             "name": "symfony/console",
-            "version": "v4.4.3",
+            "version": "v4.4.4",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/console.git",
-                "reference": "e9ee09d087e2c88eaf6e5fc0f5c574f64d100e4f"
+                "reference": "f512001679f37e6a042b51897ed24a2f05eba656"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/console/zipball/e9ee09d087e2c88eaf6e5fc0f5c574f64d100e4f",
-                "reference": "e9ee09d087e2c88eaf6e5fc0f5c574f64d100e4f",
+                "url": "https://api.github.com/repos/symfony/console/zipball/f512001679f37e6a042b51897ed24a2f05eba656",
+                "reference": "f512001679f37e6a042b51897ed24a2f05eba656",
                 "shasum": ""
             },
             "require": {
@@ -2031,7 +2031,7 @@
             ],
             "description": "Symfony Console Component",
             "homepage": "https://symfony.com",
-            "time": "2020-01-10T21:54:01+00:00"
+            "time": "2020-01-25T12:44:29+00:00"
         },
         {
             "name": "symfony/contracts",
@@ -2112,7 +2112,7 @@
         },
         {
             "name": "symfony/event-dispatcher",
-            "version": "v4.4.3",
+            "version": "v4.4.4",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/event-dispatcher.git",
@@ -2471,7 +2471,7 @@
         },
         {
             "name": "symfony/process",
-            "version": "v4.4.3",
+            "version": "v4.4.4",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/process.git",
@@ -2520,16 +2520,16 @@
         },
         {
             "name": "symfony/var-dumper",
-            "version": "v4.4.3",
+            "version": "v4.4.4",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/var-dumper.git",
-                "reference": "7cfa470bc3b1887a7b2a47c0a702a84ad614fa92"
+                "reference": "46b53fd714568af343953c039ff47b67ce8af8d6"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/var-dumper/zipball/7cfa470bc3b1887a7b2a47c0a702a84ad614fa92",
-                "reference": "7cfa470bc3b1887a7b2a47c0a702a84ad614fa92",
+                "url": "https://api.github.com/repos/symfony/var-dumper/zipball/46b53fd714568af343953c039ff47b67ce8af8d6",
+                "reference": "46b53fd714568af343953c039ff47b67ce8af8d6",
                 "shasum": ""
             },
             "require": {
@@ -2592,11 +2592,11 @@
                 "debug",
                 "dump"
             ],
-            "time": "2020-01-04T13:00:46+00:00"
+            "time": "2020-01-25T12:44:29+00:00"
         },
         {
             "name": "symfony/yaml",
-            "version": "v4.4.3",
+            "version": "v4.4.4",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/yaml.git",
@@ -5449,7 +5449,7 @@
         },
         {
             "name": "symfony/browser-kit",
-            "version": "v4.4.3",
+            "version": "v4.4.4",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/browser-kit.git",
@@ -5508,7 +5508,7 @@
         },
         {
             "name": "symfony/css-selector",
-            "version": "v4.4.3",
+            "version": "v4.4.4",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/css-selector.git",
@@ -5561,7 +5561,7 @@
         },
         {
             "name": "symfony/dom-crawler",
-            "version": "v4.4.3",
+            "version": "v4.4.4",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/dom-crawler.git",
@@ -5622,7 +5622,7 @@
         },
         {
             "name": "symfony/finder",
-            "version": "v4.4.3",
+            "version": "v4.4.4",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/finder.git",
diff --git a/system/src/Grav/Common/Flex/Pages/PageIndex.php b/system/src/Grav/Common/Flex/Pages/PageIndex.php
index f6118a2ae..31e94875e 100644
--- a/system/src/Grav/Common/Flex/Pages/PageIndex.php
+++ b/system/src/Grav/Common/Flex/Pages/PageIndex.php
@@ -145,7 +145,7 @@ class PageIndex extends FlexPageIndex
             /** @var PageObject $root */
             $root = $this->getFlexDirectory()->createObject($row, '/', false);
             $root->name('root.md');
-            $root->root = true;
+            $root->root(true);
 
             $this->_root = $root;
         }
diff --git a/system/src/Grav/Common/Flex/Users/UserObject.php b/system/src/Grav/Common/Flex/Users/UserObject.php
index b63f19f17..651ebd6a3 100644
--- a/system/src/Grav/Common/Flex/Users/UserObject.php
+++ b/system/src/Grav/Common/Flex/Users/UserObject.php
@@ -487,6 +487,9 @@ class UserObject extends FlexObject implements UserInterface, MediaManipulationI
         return $this->_storage;
     }
 
+    /**
+     * @return bool
+     */
     public function isValid(): bool
     {
         return $this->getProperty('state') !== null;
diff --git a/system/src/Grav/Common/Page/Pages.php b/system/src/Grav/Common/Page/Pages.php
index be30150e5..25d8f64ca 100644
--- a/system/src/Grav/Common/Page/Pages.php
+++ b/system/src/Grav/Common/Page/Pages.php
@@ -15,6 +15,8 @@ use Grav\Common\Data\Blueprint;
 use Grav\Common\Data\Blueprints;
 use Grav\Common\Debugger;
 use Grav\Common\Filesystem\Folder;
+use Grav\Common\Flex\Pages\PageCollection;
+use Grav\Common\Flex\Pages\PageIndex;
 use Grav\Common\Grav;
 use Grav\Common\Language\Language;
 use Grav\Common\Page\Interfaces\PageCollectionInterface;
@@ -1351,6 +1353,7 @@ class Pages
         $config = $this->grav['config'];
 
         // TODO: right now we are just emulating normal pages, it is inefficient and bad... but works!
+        /** @var PageCollection|PageIndex $collection */
         $collection = $directory->getIndex(null, 'storage_key');
         $cache = $directory->getCache('index');
 
diff --git a/system/src/Grav/Common/Processors/InitializeProcessor.php b/system/src/Grav/Common/Processors/InitializeProcessor.php
index bf6b20629..2ec0f4960 100644
--- a/system/src/Grav/Common/Processors/InitializeProcessor.php
+++ b/system/src/Grav/Common/Processors/InitializeProcessor.php
@@ -13,11 +13,11 @@ use Grav\Common\Config\Config;
 use Grav\Common\Debugger;
 use Grav\Common\Page\Pages;
 use Grav\Common\Plugins;
+use Grav\Common\Session;
 use Grav\Common\Uri;
 use Grav\Common\Utils;
 use Grav\Framework\Psr7\Response;
 use Grav\Framework\Session\Exceptions\SessionException;
-use Grav\Framework\Session\SessionInterface;
 use Monolog\Formatter\LineFormatter;
 use Monolog\Handler\SyslogHandler;
 use Psr\Http\Message\ResponseInterface;
@@ -211,7 +211,7 @@ class InitializeProcessor extends ProcessorBase
             // TODO: remove in 2.0.
             $this->container['accounts'];
 
-            /** @var SessionInterface $session */
+            /** @var Session $session */
             $session = $this->container['session'];
 
             try {
diff --git a/system/src/Grav/Common/User/DataUser/User.php b/system/src/Grav/Common/User/DataUser/User.php
index 7b403ad56..ecd24400c 100644
--- a/system/src/Grav/Common/User/DataUser/User.php
+++ b/system/src/Grav/Common/User/DataUser/User.php
@@ -80,6 +80,9 @@ class User extends Data implements UserInterface
         return $value;
     }
 
+    /**
+     * @return bool
+     */
     public function isValid(): bool
     {
         return $this->items !== null;
diff --git a/system/src/Grav/Framework/Acl/Access.php b/system/src/Grav/Framework/Acl/Access.php
index 6232652c2..7a8681528 100644
--- a/system/src/Grav/Framework/Acl/Access.php
+++ b/system/src/Grav/Framework/Acl/Access.php
@@ -62,7 +62,12 @@ class Access implements \JsonSerializable, \IteratorAggregate, \Countable
         $inherited = array_diff_key($parent->getAllActions(), $acl);
 
         $this->inherited += $parent->inherited + array_fill_keys(array_keys($inherited), $name ?? $parent->getName());
-        $this->acl = array_replace($acl, $inherited);
+        $acl = array_replace($acl, $inherited);
+        if (null === $acl) {
+            throw new \RuntimeException('Internal error');
+        }
+
+        $this->acl = $acl;
     }
 
     /**
diff --git a/system/src/Grav/Framework/Acl/Action.php b/system/src/Grav/Framework/Acl/Action.php
index 9edfe6ad7..8b35afe27 100644
--- a/system/src/Grav/Framework/Acl/Action.php
+++ b/system/src/Grav/Framework/Acl/Action.php
@@ -91,7 +91,8 @@ class Action implements \IteratorAggregate, \Countable
 
     public function getScope(): string
     {
-        if (($pos = strpos($this->name, '.')) > 0) {
+        $pos = strpos($this->name, '.');
+        if ($pos > 0) {
             return substr($this->name, 0, $pos);
         }
 
diff --git a/system/src/Grav/Framework/Acl/Permissions.php b/system/src/Grav/Framework/Acl/Permissions.php
index b927b4eef..19874c1eb 100644
--- a/system/src/Grav/Framework/Acl/Permissions.php
+++ b/system/src/Grav/Framework/Acl/Permissions.php
@@ -16,6 +16,8 @@ class Permissions implements \ArrayAccess, \Countable, \IteratorAggregate
     /** @var Action[] */
     protected $actions = [];
     /** @var array */
+    protected $nested = [];
+    /** @var array */
     protected $types = [];
 
     /**
@@ -125,7 +127,12 @@ class Permissions implements \ArrayAccess, \Countable, \IteratorAggregate
      */
     public function addTypes(array $types): void
     {
-        $this->types = array_replace($this->types, $types);
+        $types = array_replace($this->types, $types);
+        if (null === $types) {
+            throw new \RuntimeException('Internal error');
+        }
+
+        $this->types = $types;
     }
 
     /**
diff --git a/system/src/Grav/Framework/Acl/PermissionsReader.php b/system/src/Grav/Framework/Acl/PermissionsReader.php
index c031e3f8b..d3bdb3b00 100644
--- a/system/src/Grav/Framework/Acl/PermissionsReader.php
+++ b/system/src/Grav/Framework/Acl/PermissionsReader.php
@@ -21,6 +21,7 @@ class PermissionsReader
      */
     public static function fromYaml(string $filename): array
     {
+        /** @var array $content */
         $content = CompiledYamlFile::instance($filename)->content();
         $actions = $content['actions'] ?? [];
         $types = $content['types'] ?? [];
@@ -101,7 +102,7 @@ class PermissionsReader
             }
             unset($val);
         }
-        $dependencies = json_decode(json_encode($dependencies), true);
+        $dependencies = json_decode(json_encode($dependencies, JSON_THROW_ON_ERROR), true);
 
         foreach (static::getDependencies($dependencies) as $type) {
             $defaults = $types[$type] ?? null;
@@ -158,6 +159,9 @@ class PermissionsReader
             $scopes[] = $action;
 
             $action = array_replace_recursive(...$scopes);
+            if (null === $action) {
+                throw new \RuntimeException('Internal error');
+            }
 
             $newType =  $defaults['type'] ?? null;
             if ($newType && $newType !== $type) {
diff --git a/system/src/Grav/Framework/Flex/Flex.php b/system/src/Grav/Framework/Flex/Flex.php
index 5ddb513ee..a966c65f0 100644
--- a/system/src/Grav/Framework/Flex/Flex.php
+++ b/system/src/Grav/Framework/Flex/Flex.php
@@ -61,6 +61,9 @@ class Flex implements FlexInterface
     public function addDirectoryType(string $type, string $blueprint, array $config = [])
     {
         $config = array_replace_recursive(['enabled' => true], $this->config ?? [], $config);
+        if ($config === null) {
+            throw new \RuntimeException('Internal error');
+        }
 
         $this->types[$type] = new FlexDirectory($type, $blueprint, $config);
 
diff --git a/system/src/Grav/Framework/Flex/FlexDirectory.php b/system/src/Grav/Framework/Flex/FlexDirectory.php
index 78c70292f..067a5b8af 100644
--- a/system/src/Grav/Framework/Flex/FlexDirectory.php
+++ b/system/src/Grav/Framework/Flex/FlexDirectory.php
@@ -202,6 +202,7 @@ class FlexDirectory implements FlexAuthorizeInterface
 
         /** @var UniformResourceLocator $locator */
         $locator = $grav['locator'];
+        /** @var string $filename Filename is always string */
         $filename = $locator->findResource($this->getDirectoryConfigUri($name), true, true);
 
         $file = YamlFile::instance($filename);
@@ -224,6 +225,9 @@ class FlexDirectory implements FlexAuthorizeInterface
         /** @var UniformResourceLocator $locator */
         $locator = $grav['locator'];
         $filename = $locator->findResource($this->getDirectoryConfigUri($name), true);
+        if ($filename === false) {
+            return [];
+        }
 
         $file = YamlFile::instance($filename);
 
diff --git a/system/src/Grav/Framework/Flex/FlexDirectoryForm.php b/system/src/Grav/Framework/Flex/FlexDirectoryForm.php
index 00c5db582..4cd721ec2 100644
--- a/system/src/Grav/Framework/Flex/FlexDirectoryForm.php
+++ b/system/src/Grav/Framework/Flex/FlexDirectoryForm.php
@@ -43,7 +43,7 @@ class FlexDirectoryForm implements FlexDirectoryFormInterface, \JsonSerializable
     /** @var array|null */
     private $form;
 
-    /** @var FlexDirectory|null */
+    /** @var FlexDirectory */
     private $directory;
 
     /** @var string */
@@ -116,7 +116,11 @@ class FlexDirectoryForm implements FlexDirectoryFormInterface, \JsonSerializable
             $data = $flash->getData();
             $includeOriginal = (bool)($this->getBlueprint()->form()['images']['original'] ?? null);
 
-            $this->directory = $flash->getDirectory();
+            $directory = $flash->getDirectory();
+            if (null === $directory) {
+                throw new \RuntimeException('Flash has no directory');
+            }
+            $this->directory = $directory;
             $this->data = $data ? new Data($data, $this->getBlueprint()) : null;
             $this->files = $flash->getFilesByFields($includeOriginal);
         }
@@ -191,6 +195,10 @@ class FlexDirectoryForm implements FlexDirectoryFormInterface, \JsonSerializable
      */
     public function getData()
     {
+        if (null === $this->data) {
+            $this->data = new Data([], $this->getBlueprint());
+        }
+
         return $this->data;
     }
 
@@ -262,7 +270,7 @@ class FlexDirectoryForm implements FlexDirectoryFormInterface, \JsonSerializable
     }
 
     /**
-     * @return FlexObjectInterface
+     * @return FlexDirectory
      */
     public function getDirectory(): FlexDirectory
     {
@@ -277,9 +285,6 @@ class FlexDirectoryForm implements FlexDirectoryFormInterface, \JsonSerializable
         if (null === $this->blueprint) {
             try {
                 $blueprint = $this->getDirectory()->getDirectoryBlueprint();
-                if (!$blueprint) {
-                    throw new \RuntimeException('Blueprint not found');
-                }
                 if ($this->form) {
                     // We have field overrides available.
                     $blueprint->extend(['form' => $this->form], true);
diff --git a/system/src/Grav/Framework/Flex/FlexForm.php b/system/src/Grav/Framework/Flex/FlexForm.php
index 86c9e101b..c9a875297 100644
--- a/system/src/Grav/Framework/Flex/FlexForm.php
+++ b/system/src/Grav/Framework/Flex/FlexForm.php
@@ -140,7 +140,11 @@ class FlexForm implements FlexObjectFormInterface, \JsonSerializable
             }
             $includeOriginal = (bool)($this->getBlueprint()->form()['images']['original'] ?? null);
 
-            $this->object = $flash->getObject();
+            $object = $flash->getObject();
+            if (null === $object) {
+                throw new \RuntimeException('Flash has no object');
+            }
+            $this->object = $object;
             $this->data = $data;
             $this->files = $flash->getFilesByFields($includeOriginal);
         }
diff --git a/system/src/Grav/Framework/Flex/FlexFormFlash.php b/system/src/Grav/Framework/Flex/FlexFormFlash.php
index 9943a285c..dcbdae80c 100644
--- a/system/src/Grav/Framework/Flex/FlexFormFlash.php
+++ b/system/src/Grav/Framework/Flex/FlexFormFlash.php
@@ -20,7 +20,7 @@ class FlexFormFlash extends FormFlash
     /** @var FlexObjectInterface|null */
     protected $object;
 
-    /** @var Flex */
+    /** @var FlexInterface */
     static protected $flex;
 
     public static function setFlex(FlexInterface $flex): void
diff --git a/system/src/Grav/Framework/Flex/FlexObject.php b/system/src/Grav/Framework/Flex/FlexObject.php
index 30731e524..608a15780 100644
--- a/system/src/Grav/Framework/Flex/FlexObject.php
+++ b/system/src/Grav/Framework/Flex/FlexObject.php
@@ -863,7 +863,7 @@ class FlexObject implements FlexObjectInterface, FlexAuthorizeInterface
             $grav = Grav::instance();
             /** @var Flex|null $flex */
             $flex = $grav['flex'];
-            $directory = $flex->getDirectory($type);
+            $directory = $flex ? $flex->getDirectory($type) : null;
             if (!$directory) {
                 throw new \InvalidArgumentException("Cannot unserialize Flex type '{$type}': Directory not found");
             }
diff --git a/system/src/Grav/Framework/Flex/Pages/FlexPageObject.php b/system/src/Grav/Framework/Flex/Pages/FlexPageObject.php
index d0c5b0a2d..ed937bb2a 100644
--- a/system/src/Grav/Framework/Flex/Pages/FlexPageObject.php
+++ b/system/src/Grav/Framework/Flex/Pages/FlexPageObject.php
@@ -173,7 +173,7 @@ class FlexPageObject extends FlexObject implements PageInterface, MediaManipulat
             case 'route':
                 return $this->hasKey() ? '/' . $this->getKey() : null;
             case 'header.permissions.groups':
-                return json_decode(json_encode($this->getPermissions()), true);
+                return json_decode(json_encode($this->getPermissions(), JSON_THROW_ON_ERROR), true);
         }
 
         return parent::getFormValue($name, $default, $separator);
diff --git a/system/src/Grav/Framework/Flex/Pages/Traits/PageRoutableTrait.php b/system/src/Grav/Framework/Flex/Pages/Traits/PageRoutableTrait.php
index bfcaa7453..ee5f9d78d 100644
--- a/system/src/Grav/Framework/Flex/Pages/Traits/PageRoutableTrait.php
+++ b/system/src/Grav/Framework/Flex/Pages/Traits/PageRoutableTrait.php
@@ -529,10 +529,15 @@ trait PageRoutableTrait
     /**
      * Returns whether or not this page is the root node of the pages tree.
      *
+     * @param bool|null $var
      * @return bool True if it is the root
      */
-    public function root(): bool
+    public function root($var = null): bool
     {
+        if (null !== $var) {
+            $this->root = (bool)$var;
+        }
+
         return $this->root === true || $this->getKey() === '/';
     }
 
diff --git a/system/src/Grav/Framework/Flex/Storage/FolderStorage.php b/system/src/Grav/Framework/Flex/Storage/FolderStorage.php
index c90d15ce1..c41d7da6b 100644
--- a/system/src/Grav/Framework/Flex/Storage/FolderStorage.php
+++ b/system/src/Grav/Framework/Flex/Storage/FolderStorage.php
@@ -404,6 +404,7 @@ class FolderStorage extends AbstractFilesystemStorage
      */
     protected function deleteFile(File $file)
     {
+        $filename = $file->filename();
         try {
             $data = $file->content();
             if ($file->exists()) {
@@ -412,11 +413,11 @@ class FolderStorage extends AbstractFilesystemStorage
 
             /** @var UniformResourceLocator $locator */
             $locator = Grav::instance()['locator'];
-            if ($locator->isStream($file->filename())) {
-                $locator->clearCache($file->filename());
+            if ($locator->isStream($filename)) {
+                $locator->clearCache($filename);
             }
         } catch (\RuntimeException $e) {
-            throw new \RuntimeException(sprintf('Flex deleteFile(%s): %s', $file->filename(), $e->getMessage()));
+            throw new \RuntimeException(sprintf('Flex deleteFile(%s): %s', $filename, $e->getMessage()));
         }
 
         return $data;
diff --git a/system/src/Grav/Framework/Form/Traits/FormTrait.php b/system/src/Grav/Framework/Form/Traits/FormTrait.php
index 2d264b667..9fbf8e28b 100644
--- a/system/src/Grav/Framework/Form/Traits/FormTrait.php
+++ b/system/src/Grav/Framework/Form/Traits/FormTrait.php
@@ -218,26 +218,41 @@ trait FormTrait
         return $this;
     }
 
+    /**
+     * @return bool
+     */
     public function isValid(): bool
     {
         return $this->status === 'success';
     }
 
+    /**
+     * @return string|null
+     */
     public function getError(): ?string
     {
         return !$this->isValid() ? $this->message : null;
     }
 
+    /**
+     * @return array
+     */
     public function getErrors(): array
     {
         return !$this->isValid() ? $this->messages : [];
     }
 
+    /**
+     * @return bool
+     */
     public function isSubmitted(): bool
     {
         return $this->submitted;
     }
 
+    /**
+     * @return bool
+     */
     public function validate(): bool
     {
         if (!$this->isValid()) {
@@ -309,16 +324,25 @@ trait FormTrait
         $this->flash = null;
     }
 
+    /**
+     * @return array
+     */
     public function getFields(): array
     {
         return $this->getBlueprint()->fields();
     }
 
+    /**
+     * @return array
+     */
     public function getButtons(): array
     {
         return $this->getBlueprint()->get('form/buttons') ?? [];
     }
 
+    /**
+     * @return array
+     */
     public function getTasks(): array
     {
         return $this->getBlueprint()->get('form/tasks') ?? [];
diff --git a/system/src/Grav/Framework/Route/RouteFactory.php b/system/src/Grav/Framework/Route/RouteFactory.php
index 228048e5c..08f695abc 100644
--- a/system/src/Grav/Framework/Route/RouteFactory.php
+++ b/system/src/Grav/Framework/Route/RouteFactory.php
@@ -90,7 +90,7 @@ class RouteFactory
     }
 
     /**
-     * @param $root
+     * @param string $root
      */
     public static function setRoot($root): void
     {
diff --git a/system/src/Grav/Framework/Session/Session.php b/system/src/Grav/Framework/Session/Session.php
index 26e0c6847..88cb44ce8 100644
--- a/system/src/Grav/Framework/Session/Session.php
+++ b/system/src/Grav/Framework/Session/Session.php
@@ -206,7 +206,7 @@ class Session implements SessionInterface
         $this->onSessionStart();
 
         $user = $this->__get('user');
-        if ($user && (!$user instanceof UserInterface || !$user->isValid())) {
+        if ($user && (!$user instanceof UserInterface || (method_exists($user, 'isValid') && !$user->isValid()))) {
             $this->invalidate();
 
             throw new SessionException('Invalid User object, session destroyed.', 500);
diff --git a/tests/phpstan/phpstan.neon b/tests/phpstan/phpstan.neon
index 9e8dcb36a..9f3d21c5b 100644
--- a/tests/phpstan/phpstan.neon
+++ b/tests/phpstan/phpstan.neon
@@ -28,11 +28,15 @@ parameters:
 
         # TODO: Errors that needs some more thinking (bad design?)
         - '#Access to an undefined property RocketTheme\\Toolbox\\Event\\Event::#'
+        - '#Instantiation of deprecated class RocketTheme\\Toolbox\\Event\\Event#'
+        - '#extends deprecated class RocketTheme\\Toolbox\\Event\\Event#'
+        - '#implements deprecated interface RocketTheme\\Toolbox\\Event\\EventSubscriberInterface#'
         - '#Access to an undefined property Grav\\Common\\Data\\Blueprint::#'
         - '#Access to an undefined property Grav\\Common\\Media\\Interfaces\\MediaObjectInterface::#'
         -
             message: '#Cannot call method path\(\) on string#'
             path: 'system/src/Grav/Common/Page/Media.php'
+        - '"FlexCollectionInterface::filterBy\(\) invoked with 2 parameters"'
 
         # TODO: system.twig.umask_fix will not work with Twig 2 anymore
         -