All my Ubuntu servers on ISPConfig's Monitor tab are blue, suggesting there's an update. When going to Status Update there are no updates mentioned but only Ubuntu Pro advertising. How can I get rid of that, so my servers turn green again (or blue when there really is an update).
Many Ubuntu users reported this as a bug already to Ubuntu as the purpose of apt hooks are not to display ads and it's in their issue tracker, so it will most likely get fixed by them. If not, we will apply a fix to remove their ads from apt output. In the meantime, have a look here: https://git.ispconfig.org/ispconfig/ispconfig3/-/issues/6392
It is basically not a bug though it can be said as one too. To overcome this, for personal user, they can simply use their UbuntuOne account to get the free personal subscription for up to 5 servers per UbuntuOne account and then attach the token to their server(s). If they have more than 5 ubuntu servers or if they want to have more than one email, thus one different token per server, they might need more than one UbuntuOne account. Otherwise, may be ISPConfig want to fix that in its next release but that might be quite tedious.
https://ubuntu.com/pro and scroll down to "Free for personal use". Don't do it if you use these servers for any business operation tho.