diff --git a/Adapter/AdapterInterface.php b/Adapter/AdapterInterface.php
index 9d42c01..40d7a2b 100644
--- a/Adapter/AdapterInterface.php
+++ b/Adapter/AdapterInterface.php
@@ -19,7 +19,7 @@ public function has(string $path): bool;
      * @param array $config
      * @return bool
      */
-    public function write(string $path, string $contents, array $config = []): bool;
+    public function write(string $path, $contents, array $config = []): bool;
 
     /**
      * @param string $path
@@ -35,7 +35,7 @@ public function writeStream(string $path, $resource, array $config = []): bool;
      * @param array $config
      * @return bool
      */
-    public function put(string $path, string $contents, array $config = []): bool;
+    public function put(string $path, $contents, array $config = []): bool;
 
     /**
      * @param string $path
@@ -57,7 +57,7 @@ public function readAndDelete(string $path);
      * @param array $config
      * @return bool
      */
-    public function update(string $path, string $contents, array $config = []): bool;
+    public function update(string $path, $contents, array $config = []): bool;
 
     /**
      * @param string $path
@@ -117,7 +117,7 @@ public function createDir(string $dirname, array $config = []): bool;
      * @param bool $recursive
      * @return array|null
      */
-    public function listContents(string $directory = '', bool $recursive = false): ?array;
+    public function listContents(string $directory = '', bool $recursive = false);
 
     /**
      * @param string $path
diff --git a/Adapter/FilesystemAdapter.php b/Adapter/FilesystemAdapter.php
index e5f14b0..baa6ad2 100644
--- a/Adapter/FilesystemAdapter.php
+++ b/Adapter/FilesystemAdapter.php
@@ -39,7 +39,7 @@ public function has(string $path): bool
      * @return bool
      * @throws \League\Flysystem\FileExistsException
      */
-    public function write(string $path, ?string $contents, array $config = []): bool
+    public function write(string $path, $contents, array $config = []): bool
     {
         return $this->filesystem->write($path, $contents, $config);
     }
@@ -62,7 +62,7 @@ public function writeStream(string $path, $resource, array $config = []): bool
      * @param array $config
      * @return bool
      */
-    public function put(string $path, ?string $contents, array $config = []): bool
+    public function put(string $path, $contents, array $config = []): bool
     {
         return $this->filesystem->put($path, $contents, $config);
     }
@@ -95,7 +95,7 @@ public function readAndDelete(string $path)
      * @return bool
      * @throws \League\Flysystem\FileNotFoundException
      */
-    public function update(string $path, ?string $contents, array $config = []): bool
+    public function update(string $path, $contents, array $config = []): bool
     {
         return $this->filesystem->update($path, $contents, $config);
     }
@@ -190,7 +190,7 @@ public function createDir(string $dirname, array $config = []): bool
      * @param bool $recursive
      * @return array|null
      */
-    public function listContents(string $directory = '', bool $recursive = false): ?array
+    public function listContents(string $directory = '', bool $recursive = false)
     {
         return $this->filesystem->listContents($directory, $recursive);
     }
diff --git a/Block/Adminhtml/Filesystem/Content.php b/Block/Adminhtml/Filesystem/Content.php
index d3366b0..c167ae5 100644
--- a/Block/Adminhtml/Filesystem/Content.php
+++ b/Block/Adminhtml/Filesystem/Content.php
@@ -100,7 +100,7 @@ protected function _construct()
     /**
      * @return string|null
      */
-    public function getFilebrowserSetupObject(): ?string
+    public function getFilebrowserSetupObject()
     {
         $setupObject = [
             'newFolderPrompt' => __('New Folder Name:'),
@@ -186,7 +186,7 @@ public function getWysiwygModalUrl(): string
     /**
      * @return string|null
      */
-    public function getTargetElementId(): ?string
+    public function getTargetElementId()
     {
         return (string)$this->getRequest()->getParam('target_element_id');
     }
@@ -194,7 +194,7 @@ public function getTargetElementId(): ?string
     /**
      * @return string|null
      */
-    public function getModalIdentifier(): ?string
+    public function getModalIdentifier()
     {
         return (string)$this->getRequest()->getParam('identifier');
     }
diff --git a/Block/Adminhtml/Filesystem/Content/Files.php b/Block/Adminhtml/Filesystem/Content/Files.php
index eb071d5..6455eaf 100644
--- a/Block/Adminhtml/Filesystem/Content/Files.php
+++ b/Block/Adminhtml/Filesystem/Content/Files.php
@@ -146,7 +146,7 @@ public function getFilesCount(): int
      * @param array $file
      * @return string|null
      */
-    public function getFileId(array $file): ?string
+    public function getFileId(array $file)
     {
         if(!isset($file['path'])) {
             return null;
@@ -158,7 +158,7 @@ public function getFileId(array $file): ?string
      * @param array $file
      * @return string|null
      */
-    public function getFileShortName(array $file): ?string {
+    public function getFileShortName(array $file) {
         if(!isset($file['path'])) {
             return null;
         }
diff --git a/Block/Adminhtml/Filesystem/Content/Uploader.php b/Block/Adminhtml/Filesystem/Content/Uploader.php
index fe4a0b8..6920310 100644
--- a/Block/Adminhtml/Filesystem/Content/Uploader.php
+++ b/Block/Adminhtml/Filesystem/Content/Uploader.php
@@ -40,7 +40,7 @@ protected function _construct()
     /**
      * @return string|null
      */
-    protected function _getMediaType(): ?string
+    protected function _getMediaType()
     {
         if ($this->hasData('media_type')) {
             return $this->_getData('media_type');
diff --git a/Block/Adminhtml/Filesystem/Tree.php b/Block/Adminhtml/Filesystem/Tree.php
index 524f3d0..715e2e9 100644
--- a/Block/Adminhtml/Filesystem/Tree.php
+++ b/Block/Adminhtml/Filesystem/Tree.php
@@ -52,7 +52,7 @@ public function __construct(
      * @return string|null
      * @throws \Exception
      */
-    public function getTreeJson(): ?string
+    public function getTreeJson()
     {
         $jsonArray = [];
 
@@ -125,7 +125,7 @@ public function getTreeCurrentPath(): array
     /**
      * @return string|null
      */
-    public function getTreeWidgetOptions(): ?string
+    public function getTreeWidgetOptions()
     {
         $serialized = $this->_serializer->serialize([
             "folderTree" => [
diff --git a/Helper/Config.php b/Helper/Config.php
index 5ba83a6..73738ec 100644
--- a/Helper/Config.php
+++ b/Helper/Config.php
@@ -69,7 +69,7 @@ public function __construct(
     /**
      * @return string|null
      */
-    public function getSource(): ?string
+    public function getSource()
     {
         return $this->_scopeConfig->getValue(self::XPATH_CONFIG_GENERAL_SOURCE);
     }
@@ -85,7 +85,7 @@ public function getFileComparingEnabled(): bool
     /**
      * @return string|null
      */
-    public function getLocalPath(): ?string
+    public function getLocalPath()
     {
         return $this->_scopeConfig->getValue(self::XPATH_CONFIG_LOCAL_PATH);
     }
@@ -101,7 +101,7 @@ public function getLocalLock(): int
     /**
      * @return string|null
      */
-    public function getFtpHost(): ?string
+    public function getFtpHost()
     {
         return $this->_scopeConfig->getValue(self::XPATH_CONFIG_FTP_HOST);
     }
@@ -109,7 +109,7 @@ public function getFtpHost(): ?string
     /**
      * @return string|null
      */
-    public function getFtpUser(): ?string
+    public function getFtpUser()
     {
         return $this->_scopeConfig->getValue(self::XPATH_CONFIG_FTP_USER);
     }
@@ -117,7 +117,7 @@ public function getFtpUser(): ?string
     /**
      * @return string|null
      */
-    public function getFtpPassword(): ?string
+    public function getFtpPassword()
     {
         return $this->_scopeConfig->getValue(self::XPATH_CONFIG_FTP_PASSWORD);
     }
@@ -133,7 +133,7 @@ public function getFtpPort(): int
     /**
      * @return string|null
      */
-    public function getFtpPath(): ?string
+    public function getFtpPath()
     {
         return $this->_scopeConfig->getValue(self::XPATH_CONFIG_FTP_PATH);
     }
@@ -165,7 +165,7 @@ public function getFtpTimeout(): int
     /**
      * @return string|null
      */
-    public function getSftpHost(): ?string
+    public function getSftpHost()
     {
         return $this->_scopeConfig->getValue(self::XPATH_CONFIG_SFTP_HOST);
     }
@@ -181,7 +181,7 @@ public function getSftpPort(): int
     /**
      * @return string|null
      */
-    public function getSftpUsername(): ?string
+    public function getSftpUsername()
     {
         return $this->_scopeConfig->getValue(self::XPATH_CONFIG_SFTP_USERNAME);
     }
@@ -189,7 +189,7 @@ public function getSftpUsername(): ?string
     /**
      * @return string|null
      */
-    public function getSftpPassword(): ?string
+    public function getSftpPassword()
     {
         return $this->_scopeConfig->getValue(self::XPATH_CONFIG_SFTP_PASSWORD);
     }
@@ -197,7 +197,7 @@ public function getSftpPassword(): ?string
     /**
      * @return string|null
      */
-    public function getSftpPrivateKeyPath(): ?string
+    public function getSftpPrivateKeyPath()
     {
         return $this->_scopeConfig->getValue(self::XPATH_CONFIG_SFTP_PRIVATE_KEY_PATH);
     }
@@ -205,7 +205,7 @@ public function getSftpPrivateKeyPath(): ?string
     /**
      * @return string|null
      */
-    public function getSftpPrivateKeyContent(): ?string
+    public function getSftpPrivateKeyContent()
     {
         return $this->_scopeConfig->getValue(self::XPATH_CONFIG_SFTP_PRIVATE_KEY_CONTENT);
     }
@@ -213,7 +213,7 @@ public function getSftpPrivateKeyContent(): ?string
     /**
      * @return string|null
      */
-    public function getSftpRoot(): ?string
+    public function getSftpRoot()
     {
         return $this->_scopeConfig->getValue(self::XPATH_CONFIG_SFTP_ROOT);
     }
@@ -229,7 +229,7 @@ public function getSftpTimeout(): int
     /**
      * @return int|null
      */
-    public function getSftpDirectoryPermissions(): ?int
+    public function getSftpDirectoryPermissions()
     {
         $directoryPermissions = $this->_scopeConfig->getValue(self::XPATH_CONFIG_SFTP_DIRECTORY_PERMISSIONS);
 
diff --git a/Model/Filesystem/Manager.php b/Model/Filesystem/Manager.php
index 82dce7e..baedc0e 100644
--- a/Model/Filesystem/Manager.php
+++ b/Model/Filesystem/Manager.php
@@ -89,7 +89,7 @@ public function __construct(
      * @return FilesystemAdapter|null
      * @throws LocalizedException
      */
-    public function create(?string $source = null): ?FilesystemAdapter
+    public function create($source = null)
     {
         if (!$source) {
             $source = $this->_flysystemConfig->getSource();
@@ -120,7 +120,7 @@ public function create(?string $source = null): ?FilesystemAdapter
      * @return FilesystemAdapter|null
      * @throws LocalizedException
      */
-    public function getAdapter(bool $createIfNotExists = true): ?FilesystemAdapter
+    public function getAdapter(bool $createIfNotExists = true)
     {
         if (!$this->_adapter && $createIfNotExists) {
             $this->create();
@@ -136,7 +136,7 @@ public function getAdapter(bool $createIfNotExists = true): ?FilesystemAdapter
      * @param FilesystemAdapter|null $adapter
      * @return void
      */
-    public function setAdapter(?FilesystemAdapter $adapter)
+    public function setAdapter($adapter)
     {
         $this->_adapter = $adapter;
     }
@@ -144,7 +144,7 @@ public function setAdapter(?FilesystemAdapter $adapter)
     /**
      * @return string|null
      */
-    public function getPath(): ?string
+    public function getPath()
     {
         return $this->_path;
     }
@@ -152,7 +152,7 @@ public function getPath(): ?string
     /**
      * @param string|null $path
      */
-    public function setPath(?string $path)
+    public function setPath($path)
     {
         $this->_path = $path;
     }
@@ -161,7 +161,7 @@ public function setPath(?string $path)
      * @param string|null $path
      * @return FilesystemAdapter|null
      */
-    public function createLocalAdapter(?string $path = null): ?FilesystemAdapter
+    public function createLocalAdapter($path = null)
     {
         try {
             if (empty($path)) {
@@ -183,7 +183,7 @@ public function createLocalAdapter(?string $path = null): ?FilesystemAdapter
     /**
      * @return FilesystemAdapter|null
      */
-    protected function createFtpAdapter(): ?FilesystemAdapter
+    protected function createFtpAdapter()
     {
         try {
             $host = $this->_flysystemConfig->getFtpHost();
@@ -219,7 +219,7 @@ protected function createFtpAdapter(): ?FilesystemAdapter
     /**
      * @return FilesystemAdapter|null
      */
-    protected function createSftpAdapter(): ?FilesystemAdapter
+    protected function createSftpAdapter()
     {
         try {
             $host = $this->_flysystemConfig->getSftpHost();
@@ -284,7 +284,7 @@ public function getSession(): Session
      * @param string|null $identifier
      * @return Session
      */
-    public function setModalIdentifier(?string $identifier): Session
+    public function setModalIdentifier($identifier): Session
     {
         return $this->getSession()->setFlysystemModalId($identifier);
     }
@@ -292,7 +292,7 @@ public function setModalIdentifier(?string $identifier): Session
     /**
      * @return string|null
      */
-    public function getModalIdentifier(): ?string
+    public function getModalIdentifier()
     {
         return $this->getSession()->getFlysystemModalId();
     }
diff --git a/Model/Filesystem/TmpManager.php b/Model/Filesystem/TmpManager.php
index 8f82e8e..d1cb3e1 100644
--- a/Model/Filesystem/TmpManager.php
+++ b/Model/Filesystem/TmpManager.php
@@ -155,7 +155,7 @@ public function getDirectoryListMedia(): MagentoFilesystem\Directory\WriteInterf
     /**
      * @return FilesystemAdapter|null
      */
-    public function create(): ?FilesystemAdapter
+    public function create()
     {
         if(!$this->_adapter) {
             $path = $this->_directoryList->getAbsolutePath();
@@ -168,9 +168,10 @@ public function create(): ?FilesystemAdapter
      * @param string $file
      * @param string|null $content
      * @return bool
+     * @throws LocalizedException
      * @throws \League\Flysystem\FileExistsException
      */
-    public function writeTmp(string $file, ?string $content = null): bool
+    public function writeTmp(string $file, $content = null): bool
     {
         $this->clearTmp();
         return $this->getAdapter()->write($this->getTmpPath($file), $content);
@@ -249,7 +250,7 @@ public function clearTmp(): bool
      * @throws LocalizedException
      * @throws \League\Flysystem\FileExistsException
      */
-    public function writePreview(string $file, ?string $content = null): bool
+    public function writePreview(string $file, $content = null): bool
     {
         $this->clearPreview();
         $previewFilename = $this->getUserPreviewDir().'/'.basename($file);
@@ -286,7 +287,7 @@ public function clearPreview(): bool
     /**
      * @return FilesystemAdapter|null
      */
-    public function getAdapter(): ?FilesystemAdapter
+    public function getAdapter()
     {
         return $this->_adapter;
     }
@@ -294,7 +295,7 @@ public function getAdapter(): ?FilesystemAdapter
     /**
      * @param FilesystemAdapter|null $adapter
      */
-    public function setAdapter(?FilesystemAdapter $adapter)
+    public function setAdapter($adapter)
     {
         $this->_adapter = $adapter;
     }
@@ -307,7 +308,7 @@ public function setAdapter(?FilesystemAdapter $adapter)
      * @throws \League\Flysystem\FileExistsException
      * @throws \League\Flysystem\FileNotFoundException
      */
-    public function writeWysiwygFile(string $file, ?string $content = null): string
+    public function writeWysiwygFile(string $file, $content = null): string
     {
         $wysiwygFileConst = 'wysiwyg/'.ltrim($file, '/');
         $wysiwygFile = $wysiwygFileConst;
diff --git a/Model/Filesystem/UploadManager.php b/Model/Filesystem/UploadManager.php
index 9da939a..10454fe 100644
--- a/Model/Filesystem/UploadManager.php
+++ b/Model/Filesystem/UploadManager.php
@@ -81,7 +81,7 @@ public function __construct(
     /**
      * @return FilesystemAdapter|null
      */
-    public function create(): ?FilesystemAdapter
+    public function create()
     {
         if(!$this->_adapter) {
             $this->_adapter = $this->_flysystemFactory->create($this->_flysystemManager->createLocalDriver(self::SERVER_TMP_PATH));
@@ -92,7 +92,7 @@ public function create(): ?FilesystemAdapter
     /**
      * @return Uploader|null
      */
-    public function getUploader(): ?Uploader
+    public function getUploader()
     {
         return $this->_uploader;
     }
@@ -100,7 +100,7 @@ public function getUploader(): ?Uploader
     /**
      * @return FilesystemAdapter|null
      */
-    public function getAdapter(): ?FilesystemAdapter
+    public function getAdapter()
     {
         return $this->_adapter;
     }
diff --git a/Model/Pool/Modifier/CategoryImage.php b/Model/Pool/Modifier/CategoryImage.php
index a1753e2..3837f32 100644
--- a/Model/Pool/Modifier/CategoryImage.php
+++ b/Model/Pool/Modifier/CategoryImage.php
@@ -57,7 +57,7 @@ public function __construct(
      * @throws \League\Flysystem\FileNotFoundException
      * @throws \Magento\Framework\Exception\NoSuchEntityException
      */
-    public function modifyFile(array $data): ?string
+    public function modifyFile(array $data)
     {
         $this->filename = null;
         if(!isset($data['filename']) || empty($data['filename'])) {
@@ -66,17 +66,16 @@ public function modifyFile(array $data): ?string
 
         $this->filename = $data['filename'];
 
-        $file = $this->createFileArray($this->filename);
+        $file = $this->createFileArray();
 
         $result = $this->_tmpManager->createCategoryTmp($file);
         return json_encode($result);
     }
 
     /**
-     * @param string $filename
      * @return array
+     * @throws LocalizedException
      * @throws \League\Flysystem\FileNotFoundException
-     * @throws \Magento\Framework\Exception\LocalizedException
      */
     protected function createFileArray(): array {
         $file = [
diff --git a/Model/Pool/Modifier/CmsWysiwygImage.php b/Model/Pool/Modifier/CmsWysiwygImage.php
index 98ab337..417cd9a 100644
--- a/Model/Pool/Modifier/CmsWysiwygImage.php
+++ b/Model/Pool/Modifier/CmsWysiwygImage.php
@@ -72,7 +72,7 @@ public function __construct(
      * @throws \League\Flysystem\FileNotFoundException
      * @throws \Magento\Framework\Exception\NoSuchEntityException
      */
-    public function modifyFile(array $data): ?string
+    public function modifyFile(array $data)
     {
         $this->filename = null;
         if (!isset($data['filename']) || empty($data['filename'])) {
diff --git a/Model/Pool/Modifier/ProductImage.php b/Model/Pool/Modifier/ProductImage.php
index c5e10cb..d3f7843 100644
--- a/Model/Pool/Modifier/ProductImage.php
+++ b/Model/Pool/Modifier/ProductImage.php
@@ -56,7 +56,7 @@ public function __construct(
      * @throws \League\Flysystem\FileNotFoundException
      * @throws \Magento\Framework\Exception\LocalizedException
      */
-    public function modifyFile(array $data): ?string
+    public function modifyFile(array $data)
     {
         $this->filename = null;
         if(!isset($data['filename']) || empty($data['filename'])) {
diff --git a/Model/Pool/ModifierInterface.php b/Model/Pool/ModifierInterface.php
index a206636..da633c2 100644
--- a/Model/Pool/ModifierInterface.php
+++ b/Model/Pool/ModifierInterface.php
@@ -5,7 +5,7 @@ interface ModifierInterface
 {
     /**
      * @param array $data
-     * @return string
+     * @return string|null
      */
-    public function modifyFile(array $data): ?string;
+    public function modifyFile(array $data);
 }