I had the Jolla 1 (I feel old) and the compatibility was a real thing : even the bank application were working. I was able to use waze in the car with the phone.

I supposed it still valid, you just switched from 19xx to 20xx

Thanks !

My concern is more about the maintability.
Removing the package implies no more update, and any further update in the system can break (because there is a change in the headers somewhere, or else).

I’m able to rebuild the package from source, yes, but being able to patch it myself is a different story. That’s why I was looking for any known alternatives.