According to the latest Windows Phone Dev Podcast, week ending July 21, "the latest version of the Windows Phone OS, code named "Mango" has been released to manufacturing, and is being sent out to carriers and OEMs to begin their (sometimes long and arduous) testing process," blogged Lowdermilks.
"While the current dev version of Mango, available to App Hub developers, is "7661.WP7_5_Trial(mojobld)", the final version is being reported as build 7710."
Mango will be released at some point as a free download for existing Windows Phones, as well as becoming available on new phones from Acer, Fujitsu, LTE, Nokia and others.
You can hear the podcast below:
[Source: Windows Phone Dev Podcast]