diff --git a/phpstan.neon b/phpstan.neon
index d5581f7e..1b1ea08e 100644
--- a/phpstan.neon
+++ b/phpstan.neon
@@ -1,5 +1,5 @@
 parameters:
-  level: 2
+  level: 3
   reportUnmatchedIgnoredErrors: false
   bootstrapFiles:
     - src/flextype/defines.php
diff --git a/src/flextype/core/Entries/Entries.php b/src/flextype/core/Entries/Entries.php
index 9a65818c..9f536bf9 100755
--- a/src/flextype/core/Entries/Entries.php
+++ b/src/flextype/core/Entries/Entries.php
@@ -532,7 +532,7 @@ class Entries
             // to avoid it's running inside filterCollection() helper.
             if ($this->registry()->has('methods.fetch.params.options.filter.only')) {
                 $data = [];
-                foreach ($this->registry()->get('methods.fetch.result') as $key => $value) {
+                foreach ($this->registry()->get('methods.fetch.result', []) as $key => $value) {
                     $data[$key] = collection($value)->only($this->registry()->get('methods.fetch.params.options.filter.only'))->toArray();
                 }
                 $this->registry()->delete('methods.fetch.params.options.filter.only');
@@ -544,7 +544,7 @@ class Entries
             // to avoid it's running inside filterCollection() helper.
             if ($this->registry()->has('methods.fetch.params.options.filter.except')) {
                 $data = [];
-                foreach ($this->registry()->get('methods.fetch.result') as $key => $value) {
+                foreach ($this->registry()->get('methods.fetch.result', []) as $key => $value) {
                     $data[$key] = collection($value)->except($this->registry()->get('methods.fetch.params.options.filter.except'))->toArray();
                 }
                 $this->registry()->delete('methods.fetch.params.options.filter.except');
diff --git a/src/flextype/core/Flextype.php b/src/flextype/core/Flextype.php
index 0c3c2c27..50af63c3 100644
--- a/src/flextype/core/Flextype.php
+++ b/src/flextype/core/Flextype.php
@@ -42,7 +42,7 @@ final class Flextype
     /**
      * The Flextype Application Container.
      */
-    private static Container $container;
+    private static ContainerInterface $container;
 
     /**
      * Flextype should not be cloneable.
@@ -87,11 +87,11 @@ final class Flextype
     /**
      * Get Flextype Application Container.
      *
-     * @return Container Returns Flextype Application Container.
+     * @return ContainerInterface Returns Flextype Application Container.
      *
      * @access public
      */
-    public function container(): Container
+    public function container(): ContainerInterface
     {
         return self::$container;
     }
diff --git a/src/flextype/core/Middlewares/CsrfMiddleware.php b/src/flextype/core/Middlewares/CsrfMiddleware.php
index b318e993..40bf94b2 100644
--- a/src/flextype/core/Middlewares/CsrfMiddleware.php
+++ b/src/flextype/core/Middlewares/CsrfMiddleware.php
@@ -16,8 +16,9 @@ declare(strict_types=1);
 
 namespace Flextype\Middlewares;
 
-use Psr\Http\Message\ServerRequestInterface as Request;
-use Psr\Http\Server\RequestHandlerInterface as RequestHandler;
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\ServerRequestInterface;
+use Psr\Http\Server\RequestHandlerInterface;
 use Slim\Psr7\Response;
 
 use function Flextype\csrf;
@@ -27,10 +28,10 @@ class CsrfMiddleware
     /**
      * Invoke
      *
-     * @param  Request        $request PSR-7 request
-     * @param  RequestHandler $handler PSR-15 request handler
+     * @param  ServerRequestInterface  $request PSR-7 request
+     * @param  RequestHandlerInterface $handler PSR-15 request handler
      */
-    public function __invoke(Request $request, RequestHandler $handler): Response
+    public function __invoke(ServerRequestInterface $request, RequestHandlerInterface $handler): ResponseInterface
     {
         $response = $handler->handle($request);
         $data     = $request->getParsedBody();
diff --git a/src/flextype/helpers/image.php b/src/flextype/helpers/image.php
index c4b945e9..e12d1fd4 100644
--- a/src/flextype/helpers/image.php
+++ b/src/flextype/helpers/image.php
@@ -5,7 +5,6 @@ declare(strict_types=1);
 namespace Flextype;
 
 use Closure;
-use Intervention\Image\ImageManagerStatic as Image;
 
 use function count;
 use function function_exists;
@@ -16,11 +15,11 @@ if (! function_exists('imageFile')) {
     /**
      * Create a new image instance for image file.
      *
-     * @param  string $file    Image file.
+     * @param  string $file Image file.
      */
-    function imageFile(string $file): Image
+    function imageFile(string $file): \Intervention\Image\Image
     {
-        return Image::make($file);
+        return \Intervention\Image\ImageManagerStatic::make($file);
     }
 }
 
@@ -31,9 +30,9 @@ if (! function_exists('imageProcessFile')) {
      * @param  string $file    Image file.
      * @param  array  $options Options array.
      */
-    function imageProcessFile(string $file, array $options = [])
+    function imageProcessFile(string $file, array $options = []): mixed
     {
-        $image = Image::make($file);
+        $image = \Intervention\Image\ImageManagerStatic::make($file);
 
         if (count($options) === 0) {
             return $image;
@@ -41,7 +40,7 @@ if (! function_exists('imageProcessFile')) {
 
         if (isset($options['driver'])) {
             if (in_array($options['driver'], ['imagick', 'gd'])) {
-                Image::configure(['driver' => $options['driver']]);
+                \Intervention\Image\ImageManagerStatic::configure(['driver' => $options['driver']]);
             }
         }
 
@@ -167,6 +166,8 @@ if (! function_exists('imageProcessFile')) {
 
         $image->save($file, $options['quality'] ?? 70);
         $image->destroy();
+
+        return true;
     }
 }
 
@@ -178,11 +179,11 @@ if (! function_exists('imageCanvas')) {
      * @param  int   $height     Canvas height.
      * @param  mixed $background Canvas background.
      *
-     * @return Image Image canvas instance.
+     * @return \Intervention\Image\Image Image canvas instance.
      */
-    function imageCanvas(int $width, int $height, mixed $background = null): Image
+    function imageCanvas(int $width, int $height, mixed $background = null): \Intervention\Image\Image
     {
-        return Image::canvas($width, $height, $background);
+        return \Intervention\Image\ImageManagerStatic::canvas($width, $height, $background);
     }
 }
 
@@ -198,6 +199,6 @@ if (! function_exists('imageCache')) {
      */
     function imageCache(Closure $callback, int $lifetime = 5, bool $returnObj = false): mixed
     {
-        return Image::cache($callback, $lifetime, $returnObj);
+        return \Intervention\Image\ImageManagerStatic::cache($callback, $lifetime, $returnObj);
     }
 }
diff --git a/src/flextype/helpers/upload.php b/src/flextype/helpers/upload.php
index c8e98182..4d82261e 100644
--- a/src/flextype/helpers/upload.php
+++ b/src/flextype/helpers/upload.php
@@ -6,6 +6,7 @@ namespace Flextype;
 
 use Sirius\Upload\Handler as UploadHandler;
 use Sirius\Upload\Result\File as UploadResultFile;
+use Sirius\Upload\Result\ResultInterface;
 use Throwable;
 
 use function function_exists;
@@ -20,9 +21,9 @@ if (! function_exists('upload')) {
      * @param array  $file   Raw file data (multipart/form-data).
      * @param string $folder The folder you're targetting.
      *
-     * @return UploadResultFile Result file.
+     * @return \Sirius\Upload\Result\ResultInterface|array Result file or arrays with messages.
      */
-    function upload(array $file, string $folder): UploadResultFile
+    function upload(array $file, string $folder): \Sirius\Upload\Result\ResultInterface|array
     {
         $settings = registry()->get('flextype.settings.upload');