I don't know how useful this idea is, but let me share it, in case you like it.
I noticed the "Software" tag in the photos from my Android phone look like:
Software : JLS36I
This is an Android build ID, which in this case tells me I run Android 4.3.1 (Jelly Bean).
The full list of build IDs is available on official page:
https://source.android.com/source/build-numbers.html
Idea: when displaying the Software tag, ExifTool could additionally write the Android version, when it detects a Build ID.
(For reference, iOS writes the OS version number directly in this tag. At least in my sample file from iOS 7. E.g.:
Software : 7.1)
Thanks for the suggestion, but this opens up a whole can of worms if ExifTool tries to interpret the Software string written by all of the various software products out there.
- Phil