Altium Designer is not informing me of updates or allowing me to install them

When installing with the Offline Installer, online activity is disabled and 'greyed out'. Including the ability to check for and install updates. This is how you turn it back on.

Starting in Version: 18.0
Up to Version: Current

Solution Details

If you are unable to see new updates you may need to change the Installation Preferences to ensure this is set to Global Installation Service. If Altium Designer was installed offline it will default to offline for updates. 

To change this please go to Preferences ► System ► Installation and set the Automatic Checking to Global Installation Service.