Update 2: (July 26, 2011) Windows Phone has hit RTM…Officially. Click here for the story.
With software there is a cycle that code goes through in order to go from early builds to final. The Mango builds that reviewers and developers have enjoyed is an early beta build (7661) with some missing features. It’s been revealed by the Windows Phone Developer Podcast that Windows Phone Mango has now made it to RTM (Release to Manufacturing) state and has been sent to carriers for testing purposes, which also signifies that the coding stage is complete (build 7710).
This is a huge milestone in the whole software cycle and probably signifies that Microsoft is serious, this time, about getting the carriers on board with testing and approving the update so it is released to end-users in a timely fashion. In my time with the early Mango build, I’ve found that it is so well done that it acts like final code already, so this isn’t suprising, but solidifies the belief by many that Mango should be available in September.