diff --git a/psalm.xml b/psalm.xml
index 9dd9aef..034092e 100644
--- a/psalm.xml
+++ b/psalm.xml
@@ -1,6 +1,6 @@
 <?xml version="1.0"?>
 <psalm
-        errorLevel="1"
+        errorLevel="3"
         resolveFromConfigFile="true"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xmlns="https://getpsalm.org/schema/config"
@@ -12,4 +12,4 @@
             <directory name="src/Resources"/>
         </ignoreFiles>
     </projectFiles>
-</psalm>
\ No newline at end of file
+</psalm>
diff --git a/src/View/EditMask.php b/src/View/EditMask.php
index a5e8abe..0437e07 100644
--- a/src/View/EditMask.php
+++ b/src/View/EditMask.php
@@ -26,6 +26,7 @@
 use ContaoCommunityAlliance\DcGeneral\ContaoFrontend\Event\HandleSubmitEvent;
 use ContaoCommunityAlliance\DcGeneral\Contao\View\Contao2BackendView\Event\GetEditMaskSubHeadlineEvent;
 use ContaoCommunityAlliance\DcGeneral\Contao\View\Contao2BackendView\Event\GetEditModeButtonsEvent;
+use ContaoCommunityAlliance\DcGeneral\Controller\ControllerInterface;
 use ContaoCommunityAlliance\DcGeneral\DataDefinition\ContainerInterface;
 use ContaoCommunityAlliance\DcGeneral\DataDefinition\Definition\PropertiesDefinitionInterface;
 use ContaoCommunityAlliance\DcGeneral\DataDefinition\Palette\PaletteInterface;
@@ -180,7 +181,7 @@ public function execute()
 
             // Update the model - the model might add some more errors to the propertyValueBag via exceptions.
             $controller = $this->environment->getController();
-            assert($controller instanceof ContainerInterface);
+            assert($controller instanceof ControllerInterface);
             $controller->updateModelFromPropertyBag($this->model, $propertyValues);
         }
 
@@ -235,7 +236,7 @@ private function processInput($widgetManager): ?PropertyValueBag
 
         if ($input->getValue('FORM_SUBMIT') === $this->definition->getName()) {
             $propertyValues = new PropertyValueBag();
-            $propertyNames  = array_intersect(
+            $propertyNames  = \array_intersect(
                 $this->definition->getPropertiesDefinition()->getPropertyNames(),
                 (array) $input->getValue('FORM_INPUTS')
             );
@@ -330,7 +331,7 @@ private function getEditButtons(): array
         $button  = '<button type="submit" name="%s" id="%s" class="submit %s" accesskey="%s">%s</button>';
         $buttons = [];
 
-        $buttons['save'] = sprintf(
+        $buttons['save'] = \sprintf(
             $button,
             'save',
             'save',
@@ -340,7 +341,7 @@ private function getEditButtons(): array
         );
 
         if ($this->definition->getBasicDefinition()->isCreatable()) {
-            $buttons['saveNcreate'] = sprintf(
+            $buttons['saveNcreate'] = \sprintf(
                 $button,
                 'saveNcreate',
                 'saveNcreate',
@@ -469,9 +470,9 @@ private function storeVersion(ModelInterface $model): void
             return;
         }
 
-        $environment    = $this->environment;
-        $modelId        = $model->getId();
-        $dataProvider   = $environment->getDataProvider($this->model->getProviderName());
+        $environment  = $this->environment;
+        $modelId      = $model->getId();
+        $dataProvider = $environment->getDataProvider($this->model->getProviderName());
         assert($dataProvider instanceof DataProviderInterface);
 
         $currentVersion = $dataProvider->getActiveVersion($modelId);
diff --git a/src/View/WidgetManager.php b/src/View/WidgetManager.php
index 183b444..dad6e18 100644
--- a/src/View/WidgetManager.php
+++ b/src/View/WidgetManager.php
@@ -23,6 +23,7 @@
 
 use Contao\FormTextArea;
 use Contao\Input;
+use Contao\Widget;
 use ContaoCommunityAlliance\DcGeneral\ContaoFrontend\Event\BuildWidgetEvent;
 use ContaoCommunityAlliance\DcGeneral\Contao\View\Contao2BackendView\Event\EncodePropertyValueFromWidgetEvent;
 use ContaoCommunityAlliance\DcGeneral\ContaoFrontend\Event\DcGeneralFrontendEvents;
@@ -114,7 +115,7 @@ public function getWidget($property, PropertyValueBag $valueBag = null)
         $dispatcher->dispatch($event, DcGeneralFrontendEvents::BUILD_WIDGET);
         if (!$event->getWidget()) {
             throw new DcGeneralRuntimeException(
-                sprintf('Widget was not build for property %s::%s.', $this->model->getProviderName(), $property)
+                \sprintf('Widget was not build for property %s::%s.', $this->model->getProviderName(), $property)
             );
         }
 
@@ -174,7 +175,7 @@ public function processInput(PropertyValueBag $valueBag): void
         $post = $this->hijackPost($valueBag);
 
         // Now get and validate the widgets.
-        foreach (array_keys($valueBag->getArrayCopy()) as $property) {
+        foreach (\array_keys($valueBag->getArrayCopy()) as $property) {
             $this->processProperty($valueBag, $property);
         }
 
@@ -198,6 +199,7 @@ private function processProperty(PropertyValueBag $valueBag, string $property):
         // native data as in the model.
         // Therefore, we do not need to decode them but MUST encode them.
         $widget = $this->getWidget($property, $valueBag);
+        assert($widget instanceof Widget);
         $widget->validate();
 
         if ($widget->hasErrors()) {
@@ -217,6 +219,7 @@ private function processProperty(PropertyValueBag $valueBag, string $property):
         try {
             // See https://github.com/contao/contao/blob/7e6bacd4e/core-bundle/src/Resources/contao/forms/FormTextArea.php#L147
             if ($widget instanceof FormTextArea) {
+                /** @psalm-suppress UndefinedMagicPropertyFetch */
                 $valueBag->setPropertyValue($property, $this->encodeValue($property, $widget->rawValue, $valueBag));
                 return;
             }
@@ -276,7 +279,7 @@ private function restorePost(array $post): void
      *
      * @return EnvironmentInterface
      */
-    private function getEnvironment()
+    private function getEnvironment(): EnvironmentInterface
     {
         return $this->environment;
     }
@@ -290,7 +293,7 @@ private function getEnvironment()
      *
      * @return mixed
      */
-    private function encodeValue($property, $value, PropertyValueBag $valueBag): mixed
+    private function encodeValue(string $property, mixed $value, PropertyValueBag $valueBag): mixed
     {
         $environment = $this->getEnvironment();
 
diff --git a/src/Widgets/UploadOnSteroids.php b/src/Widgets/UploadOnSteroids.php
index d3ec9dd..4f7ca6e 100644
--- a/src/Widgets/UploadOnSteroids.php
+++ b/src/Widgets/UploadOnSteroids.php
@@ -31,6 +31,7 @@
 use Contao\Input;
 use Contao\StringUtil;
 use Contao\System;
+use Doctrine\DBAL\ArrayParameterType;
 use Doctrine\DBAL\Connection;
 use Doctrine\DBAL\Exception;
 use Doctrine\DBAL\Platforms\AbstractPlatform;
@@ -447,7 +448,7 @@ private function preOrPostFixFilename(string $filename): string
             return $filename;
         }
 
-        // We save the default delimeter '-' at prefix and postfix
+        // We save the default delimiter '-' at prefix and postfix
         // see https://github.com/ausi/slug-generator/issues/34.
         $prefix = $this->prefixFilename;
         if ($this->prefixFilename && $this->normalizeFilename) {
@@ -530,7 +531,7 @@ private function addFiles($sortBy): void
             )
             ->from($platform->quoteIdentifier('tl_files'))
             ->where($builder->expr()->in($platform->quoteIdentifier('uuid'), ':uuids'))
-            ->setParameter('uuids', (array) $this->value, Connection::PARAM_STR_ARRAY);
+            ->setParameter('uuids', (array) $this->value, ArrayParameterType::STRING );
 
         $statement = $builder->executeQuery();
         if (!$statement->rowCount()) {
@@ -705,11 +706,11 @@ protected function getSlugOptions(): array
      */
     private function translator(): TranslatorInterface
     {
-        if (!$this->filesystem) {
-            $this->filesystem = self::getContainer()->get('translator');
+        if (!$this->translator) {
+            $this->translator = self::getContainer()->get('translator');
         }
 
-        return $this->filesystem;
+        return $this->translator;
     }
 
     /**