Since version X3.23.0, you can update X3 directly from your control panel.
Login to your X3 control panel.
Navigate to Tools › X3 Updates.
If there is a new X3 version available, you will see a note and a button to "update now!".
On the X3 update page, follow on-screen instructions.
X3 updater script The X3 control panel uses the x3_updater.php script to update your X3 website. The updater script requires that your server has PHP Curl and ZipArchive extensions to be able to download and unzip X3 updates from a remote server.
Update X3 manually by FTP * Optional
If you can't or don't want to use the X3 updater script, you can also update X3 manually by FTP.