each year = new iOS/iPhone.. iPhone 2G = Firmware 1.0+ iPhone 3G = Firmware 2.0+ iPhone 3GS = Firmware 3.0+ iPhone 4 = iOS 4 iPhone 4S = iOS 5 Yearly release, just that iOS 5 took longer than previous.
yeah those were leaked on the other side of the globe when they got it first. they activated the update via itunes based on local time and transitioned from there on. ie cali got it 3 hrs later than TO/NYC or something liek that
Updated on my 3GS. Love it! Getting the iPhone 4S soon though. I don't have any performance issues with iOS5 with my 3GS. It's not like it's faster or slower though, pretty much the same just with new features. Oh and I really like how they polished up the SMS speech bubbles, etc.
i don't have it, but i know it has the drop down notification like android...its better at message popping now i heard...won't stop whatever youre doing.