diff --git a/administrator/components/com_admin/script.php b/administrator/components/com_admin/script.php
index 5422bc8ae3877..5b0eef85fe3ce 100644
--- a/administrator/components/com_admin/script.php
+++ b/administrator/components/com_admin/script.php
@@ -60,9 +60,6 @@ public function preflight($action, $installer)
                 if (array_key_exists('version', $manifestValues)) {
                     $this->fromVersion = $manifestValues['version'];
 
-                    // Ensure templates are moved to the correct mode
-                    $this->fixTemplateMode();
-
                     return true;
                 }
             }
@@ -1058,8 +1055,6 @@ public function deleteUnexistingFiles($dryRun = false, $suppressOutput = false)
             }
         }
 
-        $this->moveRemainingTemplateFiles();
-
         foreach ($folders as $folder) {
             if ($folderExists = Folder::exists(JPATH_ROOT . $folder)) {
                 $status['folders_exist'][] = $folder;
@@ -1644,84 +1639,6 @@ protected function fixFilenameCasing()
         }
     }
 
-    /**
-     * Move core template (s)css or js or image files which are left after deleting
-     * obsolete core files to the right place in media folder.
-     *
-     * @return  void
-     *
-     * @since   4.1.0
-     */
-    protected function moveRemainingTemplateFiles()
-    {
-        $folders = [
-            '/administrator/templates/atum/css'    => '/media/templates/administrator/atum/css',
-            '/administrator/templates/atum/images' => '/media/templates/administrator/atum/images',
-            '/administrator/templates/atum/js'     => '/media/templates/administrator/atum/js',
-            '/administrator/templates/atum/scss'   => '/media/templates/administrator/atum/scss',
-            '/templates/cassiopeia/css'            => '/media/templates/site/cassiopeia/css',
-            '/templates/cassiopeia/images'         => '/media/templates/site/cassiopeia/images',
-            '/templates/cassiopeia/js'             => '/media/templates/site/cassiopeia/js',
-            '/templates/cassiopeia/scss'           => '/media/templates/site/cassiopeia/scss',
-        ];
-
-        foreach ($folders as $oldFolder => $newFolder) {
-            if (Folder::exists(JPATH_ROOT . $oldFolder)) {
-                $oldPath   = realpath(JPATH_ROOT . $oldFolder);
-                $newPath   = realpath(JPATH_ROOT . $newFolder);
-                $directory = new \RecursiveDirectoryIterator($oldPath);
-                $directory->setFlags(RecursiveDirectoryIterator::SKIP_DOTS);
-                $iterator  = new \RecursiveIteratorIterator($directory);
-
-                // Handle all files in this folder and all sub-folders
-                foreach ($iterator as $oldFile) {
-                    if ($oldFile->isDir()) {
-                        continue;
-                    }
-
-                    $newFile = $newPath . substr($oldFile, strlen($oldPath));
-
-                    // Create target folder and parent folders if they don't exist yet
-                    if (is_dir(dirname($newFile)) || @mkdir(dirname($newFile), 0755, true)) {
-                        File::move($oldFile, $newFile);
-                    }
-                }
-            }
-        }
-    }
-
-    /**
-     * Ensure the core templates are correctly moved to the new mode.
-     *
-     * @return  void
-     *
-     * @since   4.1.0
-     */
-    protected function fixTemplateMode(): void
-    {
-        $db = Factory::getContainer()->get('DatabaseDriver');
-
-        array_map(
-            function ($template) use ($db) {
-                $clientId = $template === 'atum' ? 1 : 0;
-                $query = $db->getQuery(true)
-                    ->update($db->quoteName('#__template_styles'))
-                    ->set($db->quoteName('inheritable') . ' = 1')
-                    ->where($db->quoteName('template') . ' = ' . $db->quote($template))
-                    ->where($db->quoteName('client_id') . ' = ' . $clientId);
-
-                try {
-                    $db->setQuery($query)->execute();
-                } catch (Exception $e) {
-                    echo Text::sprintf('JLIB_DATABASE_ERROR_FUNCTION_FAILED', $e->getCode(), $e->getMessage()) . '<br>';
-
-                    return;
-                }
-            },
-            ['atum', 'cassiopeia']
-        );
-    }
-
     /**
      * Add the user Auth Provider Column as it could be present from 3.10 already
      *