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 Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1887959 Title: Unable to upgrade several qt5 packages (libqt5gui5, …) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/qtbase-opensource-src/+bug/1887959/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
