Support

The extension updates are handled by Joomla, not our code. In fact we are not allowed to use our own updaters. Per the Joomla Extensions Directory's terms of service all of our software must use the extensions updater built into Joomla. 

Joomla itself performs all of the update checks, determines whether there is an update available and install it. For more information on how that works you can consult our documentation.

Your problem lies in the fact that both the Core and Pro editions are the same extension for Joomla: pkg_akeeba, an extension of the type "package". What we do is provide a different update server URL in the XML manifest of our extension. It's up to Joomla to install the new update server and remove the old one when you upgrade from Akeeba Backup Core to Professional.

Now, here's a major WTF on Joomla's part. For that to happen, you need to have published the Installer - Joomla plugin. If you accidentally unpublish it Joomla no longer keeps the update site definitions (managed in Extensions, Manage, Update Sites) when you update an extension. So it's perfectly possible to install the Pro version of an extension and still have the Core update site. As a result, Joomla will then "update" your Pro version to Core as soon as it detects a new version. No warning. No external indication something is wrong. It will just blithely screw you over.

The second WTF is that Joomla may fail to remove the old update site. So now you have two update sites, one for the Pro and one for the Core edition. Which one will be used? It's anybody's guess! So, again, it's possible that the Core update site will be selected and the next time Joomla finds an update it will "update" your Pro version to Core.

There is a workaround as long as you have installed Akeeba Backup 8.0.5. Go to Extensions, Manage, Update Sites and delete all of the update sites for Akeeba Backup. Then go to Components, Akeeba Backup. This will regenerate the update site.

While you're at it, make sure that the Installer - Joomla plugin is enabled (for the reasons explained above) and the Installer - Akeeba Backup plugin is also enabled (it helps with another few Joomla bugs which make it "lose" the Download ID).