Im sure the app serio22 mentioned will work fine, but I always tell people to do this as ive learned you cant always trust what an app or gui tells you!
In terminal emulator, enter this:
What it returns is your base firmware build.
That's what I use to tell people as well but they were always confused on how to use it and read the info so I just started mentioning that app instead.. I'm not sure if it works on CM come to think of it. What I like about it is that it gives you tons of info, even how many times you've plugged into the headset jack, and charger! Lol
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