No word on that yet but rumors have it that it might be running Android 3.0! We all know that the Android 3.0 doesn't exist as of yet but some people are more than convinced:
It will feature quadband GSM/EDGE and HSPA, screen size 480 x 800, same as the
Samsung T949 (Memoir 2?), completely touch screen and not physical keyboard, Bluetooth 2.1 + EDR, aGPS. Also, a leaked screenshot shows it on T-mobile whereas it's been yelled and imposed that it's headed for Sprint.
The authenticity of all this is kinda unknown at this point but I'll keep you guys posted as and when I find more credible info.
Source:
HTC Supersonic running Android 3.0, carrier.. T-Mobile? | T Mobile News & Phone Reviews From Cell Phone Signal