The one and only possible way of automatically updating any MediaWiki website to its newer version is hosting your website on Linux cPanel based servers of SANGKRIT.net.
Otherwise there is no automatic method of upgrading MediaWiki installation, there are only manual methods such as wget, FTP, SSH File Transfer Protocol i.e. SFTP etc.
cPanel of SANGKRIT.net not only enables you to install MediaWiki in one click but also automatically update (when new versions are available) and keep backups of your MediaWiki installation.
Automatically Updating MediaWiki
First of all make sure your website is running on the servers or web-hosting (Linux) of SANGKRIT.net. And you have followed this method of installing MediaWiki on your domain.
After you click ‘+install this application’ button, the page directs you to configurations settings page where you can enable automatic updates for your MediaWiki website.
If already installed, click ‘Installatron’ from your cPanel, select ‘My Applications’ tab followed by ‘Wrench’ icon visible on your MediaWiki website’s section.
This again opens up the same configuration settings page, here you can enable automatic updates, backups etc for your website, as shown in the given screenshot.