Sorry to hear of your troubles.
spielmops wrote:So my question is: what is mgaonline, where can I get it and how do I use it?
insofar as I am aware, mgaonline is part of mgaapplet. (I am happy in my ignorance)
What I understand happens is after any update query, (and or all updates applied) mgaapplet then queries the server to see if an upgrade is available.
if there is, the upgrade notification is displayed in the system tray instead of the update icon.
If you have been seeing a notification in your system tray regarding updates, then it has been working fine.
As the good Doktor has advised, the wiki notes that the upgrade notification has not yet been enabled.
this also occurred when upgrading from Mga5 to 6, due to a ongoing issues with upgrading KDE-Plasma.
once those issues were resolved, the upgrade applet was re-enabled, and it magically appeared in users system tray.
When QA(testing) have determined to the best of their abilities that there will be minimal issues with upgrading from Mag6 to 7, there will likely be a public announcement, and shortly after, the upgrade icon notification will appear in users system trays (not yours, as you have already upgraded by a different method)