Hello Kees,
You can still open a version 10 file in 14 and work on it.
You don't need to switch to the version 14 library - just keep using the version 10 one.
Doesn't this not work for you?
In fact you can open and work on files older than 10 but the big difference with those is they don't have the built in layout book.
But the separate plotmaker file can be opened separately or it can be merged into the main file.
Personally I prefer to swap for a newer library but then I don't use the default Archicad library. I have my own custom libraries for each version.
Basically the same library each version but with some objects updtaed to make use of new features.
Therefore I don't have the migration problems with object going missing.
But then that is what the migration libraries are for I believe.
And as you mentioned you can keep all old versions installed and use those for old projects with no problems so long as your operating system will still run the old versions.
Is it mainly the libraries that you are having trouble with?
I don't do large work (just residential) so may not be aware of the problems you are experiencing.
But I still open files back to verion 6.5 (although less frequently now as I upgrade and save them when I do).
Barry.
One of the forum moderators.
Versions 6.5 to 27
i7-10700 @ 2.9Ghz, 32GB ram, GeForce RTX 2060 (6GB), Windows 10
Lenovo Thinkpad - i7-1270P 2.20 GHz, 32GB RAM, Nvidia T550, Windows 11