This probably shouldn't come as too much of a surprise, given that iOS 5 is arriving in consumers' hands next week, but Apple today gave developers a final copy of the software they can use to fine-tune their apps for compatibility.
Apple posted the gold master of the software on its developer site following this morning's announcements. Worth noting is that existing developers cannot install it as an over-the-air update, and they must use one of the recent developer betas of iTunes from the past two months.
The release today comes just after the date range predicted by Concord Securities analyst Ming-Chi Kuo. Kuo last month told AppleInsider and MacRumors that Apple should be delivering a final version of the software between September 23 and 30.
As a quick recap, iOS 5 has been in a public beta for developers since June, seeing a total of seven releases in that time:
Users get the software, which brings an overhauled notification system, iMessage, iCloud integration, and more, on October 12.