Now-a-days it is being rumoured that T-mobile is bringing an OTA update on G2 to bring new features Wi-Fi calling and Native Tathering. The ability to call over Wi-Fi as well as the ability to connect your G2 to a PC or laptop to surf the internet is known as tathering. Tethering uses mobile applications or software depending on the mobile’s operating system.
One of the users on the xda-developers forums touted that he received the new firmware over the air and it was labeled as a test. Also included in the update was a new radio image which is said to improve performance.
We can be sure that T-Mobile is doing a very limited test, can someone discovers a direct link to the OTA download? Previously, T-Mobile has in fact indicated that this functionality will be made available on all of their future Android powered smartphones and also stated that ‘Wi-Fi Calling’ functionality would be updating in LG Optimus One before it hits T-mobile G2.
In general, T-mobile release new OTAs to a limited number of users before widely distributing them.
T-Mobile’s implementation is not exactly UMA – it doesn’t transfer your calls between WiFi and T-Mo towers.
Source: xda-developers