univention-ucc-session-xenapp is not installable because the gstreamer version has changed. We should update the dependencies and check again with citrix receiver.
r70090 univention-ucc-session-xenapp 4.0.0-3.48.201606101610 r70091 Changelog
OK - univention-ucc-session-xenapp installation and gstreamer dependencies OK - Changelog
UCC 3.0 has been released. If this bug occurs again, please clone this bug.