When you see a version like say 2.0 (or 2.0.0) the first number before the first period is the Base Version, the following number would be the latest Update, and the final number would be the newest revision for the latest update. Even number for revisions (3rd set of numbers) are supposed to mean Stable Release, and odd numbers are beta (unstable) but this is not always true. Hope this helps 2. is the base version the .0 are updates .0 revisions or 2.1.1 2. is base version the .1 is the first update .1 is the latest revision so, 2.0.1 does not equal 2.1, and 2.1.1 does not equal 2.11 and vice versa. ta-da

Thank you, Captain Obvious. Please Register or Log in to view images I suspect this was pretty evident to anyone who's ever dealt with a computer before, but thank you again for posting it. You forgot to note that while firmware numbers may vary, not all firmware works for all iPods or iPhones, which is why they have iPod1,2 or iPod2,1, along with iPhone1_2.0.2 or iPhone2_2.0.2 and whatever else. That, and iPod2,1_2.1.1 is only compatible with the iPod Touch 2G. The other numbers before the 2.x.x are important too.

Well it's not such rule strict Please Register or Log in to view images author may deside how to use those numbers, he just need to keep x.y.z.v format

That sort doesn't read existing threads - they post a 'help plz' thread to ask questions and request people email answers to them.