All games I copied over from R 4.2.5 to R 5 do not run correctly. Something is always broken. Sometimes it's a simple error that you can correct afterwards, but it takes an extremely long time to find it and there is no guarantee that it will still work the next time you update. Therefore I finish all started games in 4.2.5.
So the logic that you can upgrade from 4 to 5 at any time, but not from 5 to 4, is wrong.
In the meantime there are also errors / differences between the last R 5 versions. So if you make a game professionally, you should never change. Stay with the version you started with.
But why something doesn't work can rarely be deduced logically. There is something in the engine that is calculated differently, something that is not recognized, something that has a different time priority. I have no idea. The search is tedious and annoying. I design games so that when I'm done, the executable file runs. I don't even want to know why something is different in the background...
I do not get through the ongoing releases. Every time a new package is offered in the forum, I raise by 1 so that I can distinguish them. Therefore I would be at 5.1.4...
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