Owncloud Client 2.5.2 should be installed on Ubuntu 18.10 successful.
Actual behaviour
The following packages have unmet dependencies:
owncloud-client : Depends: libowncloudsync0 (= 2.6.0.11073~daily20181128+oc-5) but it is not going to be installed
Depends: ocqt5101-libqt5concurrent5 but it is not going to be installed
Depends: ocqt5101-libqt5core5a but it is not going to be installed
Depends: ocqt5101-libqt5dbus5 but it is not going to be installed
Depends: ocqt5101-libqt5gui5 but it is not going to be installed
Depends: ocqt5101-libqt5keychain1 but it is not going to be installed
Depends: ocqt5101-libqt5network5 but it is not going to be installed
Depends: ocqt5101-libqt5webkit5 but it is not going to be installed
Depends: ocqt5101-libqt5widgets5 but it is not going to be installed
Depends: ocqt5101-libqt5xml5 but it is not going to be installed
Depends: owncloud-client-l10n but it is not going to be installed
Depends: ocqt5101-libqt5sql5-sqlite but it is not going to be installed
E: Unable to correct problems, you have held broken packages.
I see something similar (also (k)ubuntu 18.10) … I tried (there’s some history of uninstalling and so on before) the reinstall like you suggested here (remove all repos, apt-get update, wget Release.key, add key, …)
But, when finally installing the client, I see
$ sudo apt-get install owncloud-client
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
owncloud-client : Depends: libowncloudsync0 (= 2.5.1.10973+oc-10450) but it is not going to be installed
Depends: ocqt5101-libqt5core5a but it is not going to be installed
Depends: ocqt5101-libqt5dbus5 but it is not going to be installed
Depends: ocqt5101-libqt5gui5 but it is not going to be installed
Depends: ocqt5101-libqt5keychain1 but it is not going to be installed
Depends: ocqt5101-libqt5network5 but it is not going to be installed
Depends: ocqt5101-libqt5webkit5 but it is not going to be installed
Depends: ocqt5101-libqt5widgets5 but it is not going to be installed
Depends: ocqt5101-libqt5xml5 but it is not going to be installed
Depends: owncloud-client-l10n but it is not going to be installed
Depends: ocqt5101-libqt5sql5-sqlite but it is not going to be installed
E: Unable to correct problems, you have held broken packages.
Somewhere it was recommended to install all the dependencies manually, so I tried:
$ sudo apt-get install owncloud-client libowncloudsync0 ocqt5101-libqt5core5a ocqt5101-libqt5dbus5 ocqt5101-libqt5gui5 ocqt5101-libqt5keychain1 ocqt5101-libqt5network5 ocqt5101-libqt5webkit5 ocqt5101-libqt5widgets5 ocqt5101-libqt5xml5 owncloud-client-l10n ocqt5101-libqt5sql5-sqlite
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
ocqt5101-libqt5core5a : Depends: libc6 (>= 2.28) but 2.27-3ubuntu1 is to be installed
E: Unable to correct problems, you have held broken packages.
Well, libc6 is in fact <=2.28 and not jet a newer one in sight.