I’m not sure if I understand correctly. But official support for Qt 5.15 (the last and current version of Qt5) seems to be discontinued for non-paying users:
[Development] Commercial-only LTS phase starts: Closing the 5.15 branch(es) on 5th January (qt-project.org)
Does that mean that we have to port to Qt6 already if we want to see future bug fixes from upstream?
Can we continue to use Qt? Or do we have to search for alternatives?