With each new version of iOS 5, Apple extends the period until which iOS application developers can use that experimental version of the operating system. iOS 5 beta 5 expires on September 14 and now we know that iOS 5 beta 6 expires on September 29, 15 days after the previous version. Changing the expiration date is logical, but considering that it is the second expiration date for the month of September, I tend to believe that Apple will not rush the release of iOS 5 in that month, probably because it must coincide with the release of the iPhone 5.
The conference for the presentation of iOS 5 and iPhone 5 has not been established yet, and Apple usually informs journalists 2 weeks before the respective event takes place, so we may have a late conference this year. Until then, don't forget that iOS 29 beta 5 expires on September 6.