Thank you Kirk,
Finally I think I understand.
Going through my digital pictures for the past 15 years (thanks to PM+), where I used a number of different cameras, scanners and software, it is clear how this metadata works.
In the raw files the camera firmware number is written
In the jpg files the software name and version is written.
In the raw files from Panasonic G9 and Gx7 the firmware numbers are wrong. I hope you will fix the bug for both.
-Lars