In February, I shared a small snippet on the website to disable plugin update notification for a specific WordPress plugin. I found another super-small snippet to disable plugin and theme updates and installation as well as plugin editor in your or a client’s WordPress.
This single code will disable plugin and theme updates, installation and plugin/theme editor as well. It’s a single-solution for all client site problems.
Just add following snippet to your wp-config.php file:
define('DISALLOW_FILE_MODS',true);
That’s do the job! Now, only the user with FTP access can edit the plugin and theme files.