The Nokia Lumia 710 for T-Mobile is reported to receive the Windows Phone Tango update starting June 20th. The update will be available through July 31, and can be obtained by connecting your handset to the Zune Software on your computers.
T-Mobile has stated that the update will be fully managed by Microsoft, which means you won't be affected by carrier
delays when waiting for Windows Phone Tango. While the Tango update was primarily aimed at bringing support for 256MB of RAM on Windows Phones it also brings several new features and improvements.The Tango update will bring internet sharing options and will eliminate the bug which causes the keyboard to randomly disappear. Another issue users have been facing where the unlock screen randomly gets stuck will also be fixed with this update. Other improvements in the Tango update include, faster uplink speeds, improvements in the device camera, a more reliable proximity sensor and overall software stability.
You can read more about the Windows Phone Tango update here.
source – TMoNews