According to iPhone operator profiles
Jailbreak tools helped to discover this inside code-guts of current iOS devices.
It appears that some smart-guys from Yourdailymac website have just discovered the day when the next version of the popular Apple iOS system will be rolled out. It appears that we are getting iOS 5.1 on March 9th as it is indicated in carrier's profiles files.
Here is some paragraphs that clarifies the fact a bit more:
We suggest the Jailbreakers to start backing up your SHSH Blobs and stay away from the update until further indication. (A.K.A be relaxed and wait for 5.1 jailbreak).
If Steve Jobs were still between us he will be infuriated for this leak for sure
NEWS SOURCE: Operator Profiles show that iOS 5.1 may be released on March 9 (via) YourDailyMac
Our thanks again to 'Kaos2K'