Source: https://www.todhost.com/blog/introducing-the-joomla-auto-update-extension-from-joomlashowroom.html

Automatic updates is now possible with Joomla. This means if you are running Joomla 3.4.2 and there is a 3.4.4 release, your website will automatically be migrated to Joomla 3.4.4. Specialized auto-updates have been around for some time but having a component that performs this task for every Joomla installation is a great feature offered by the JoomlaShowRoom team. You need to visit their website at https://www.joomlashowroom.com/products/auto-update-for-joomla to download the extension

This will be first extension offered for the Joomla CMS to handle automatic core Joomla updates and it comes free.

That's right, just set it, forget it, and stay updated and secure.

Put your Joomla update on auto pilot
Runs with a simple cron task
Emails you when a Joomla core update is completed
Keeps your site secure
Super easy to set up
Save time updating your websites

Warning

Before you embark on any update, make sure you backup your site and download your backup to yourr local computer. Yes! download it to be double sure you have a safe backup.

Note that not all plugins and extensions will be compatible with your new update. This could cause problems on your Joomla website with new updates. The sure way to stay safe in this kind of situation is to ensure that all extensions - plugins, modules and components are running their latest versions.

Source: https://www.todhost.com/blog/introducing-the-joomla-auto-update-extension-from-joomlashowroom.html