The correct metadata here is Breaks, and it is already present, see https://salsa.debian.org/qt-kde-team/qt/qtbase/commit/78c0aa9db8684a1a. Apt didn't remove Qt 4 because you had some packages depending on it.
-- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to qtbase-opensource-src in Ubuntu. https://bugs.launchpad.net/bugs/1887959 Title: Unable to upgrade several qt5 packages (libqt5gui5, …) Status in qtbase-opensource-src package in Ubuntu: Invalid Bug description: After upgrading from Ubuntu 19.10 (maybe 18.04) to 20.04, I am unable to upgrade the packages below. The following packages have been kept back: libboost-date-time-dev libboost-dev libboost-filesystem-dev libqt5core5a libqt5dbus5 libqt5gui5 libqt5network5 libqt5printsupport5 libqt5sql5 libqt5svg5 libqt5widgets5 libqt5xml5 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/qtbase-opensource-src/+bug/1887959/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
