diff --git a/core/modules/file/lib/Drupal/file/Plugin/field/field_type/FileItem.php b/core/modules/file/lib/Drupal/file/Plugin/field/field_type/FileItem.php
index 7dac328..2341dc5 100644
--- a/core/modules/file/lib/Drupal/file/Plugin/field/field_type/FileItem.php
+++ b/core/modules/file/lib/Drupal/file/Plugin/field/field_type/FileItem.php
@@ -258,7 +258,7 @@ public static function validateExtensions($element, &$form_state) {
    * instanceSettingsForm().
    */
   public static function validateMaxFilesize($element, &$form_state) {
-      if (!empty($element['#value']) && !is_numeric(Byte::parseSize($element['#value']))) {
+      if (!empty($element['#value']) && !is_numeric(Bytes::parseSize($element['#value']))) {
       form_error($element, t('The "!name" option must contain a valid value. You may either leave the text field empty or enter a string like "512" (bytes), "80 KB" (kilobytes) or "50 MB" (megabytes).', array('!name' => t($element['title']))));
     }
   }
@@ -296,9 +296,9 @@ public function getUploadValidators() {
     $settings = $this->getFieldSettings();
 
     // Cap the upload size according to the PHP limit.
-    $max_filesize = Byte::parseSize(file_upload_max_size());
+    $max_filesize = Bytes::parseSize(file_upload_max_size());
     if (!empty($settings['max_filesize'])) {
-      $max_filesize = min($max_filesize, Byte::parseSize($settings['max_filesize']));
+      $max_filesize = min($max_filesize, Bytes::parseSize($settings['max_filesize']));
     }
 
     // There is always a file size limit due to the PHP server limit.