Which version of iOS is running on your iPhone? According to the developer of Bump on Quora almost 90% of us are running a version of iOS 4 on their iPhones. The current iOS 4.2.1 alone accounts for almost 53% and iOS 4.1 almost 28% (I suspect up to half of that might just be Jailbreak, hmm?). iOS 3.1.3 is next with over 6% which just might be some hesitant iPhone 3G users...

(If you're curious TechCrunch contrasts these with Android numbers: 2.3 is 0.4%, 2.2 is almost 52%, 2.1 is just over 35%.)

Which version of iOS are you running? Vote in the poll above and let us know why you're on your chosen version -- developer, jailbreak, performance, etc. -- in the comments!

[Quora via Techcrunch]