[Development] Deprecation/removal model going into Qt 6

[Kevin Kofler]

Manuel Bergler wrote:
> I myself don't mind the 2 weeks it took so far to upgrade from Qt 5.9 to
> Qt 5.12 in our project, that's just the cost of progress...

I guess one of the reasons that you are feeling more migration pain than the 
FOSS projects is because you skip all the non-LTS branches, whereas the FOSS 
world upgrades one branch at a time.

        Kevin Kofler