The Windows Phone Tango update is currently in testing by Australian carrier Telstra. What is being referred to as the Mango Commercial Refresh 3 update is being tested for release to the Nokia Lumia 800, HTC Mozart and HD7, Samsung Omnia W and LG c900k.
Speculation has the Tango MCR3 update being pushed out sometime in July. The update will bring these older Windows Phones current with the HTC Titan, Nokia Lumia 900 and 610 which are shipped with the updated version of Windows Phone.
Source: wpdownunder; Thanks, Peter and Sheeds, for the tip!