Windows Mobile 6.5.3 is one of the shadowy leaked builds that have popped up since Windows Mobile 6.5 devices began arriving in October. Adding support for capacitive touch, multi-touch and a variety of user interface improvements that replace legacy menu and navigation elements, Windows Mobile 6.5.3 is believed to be Microsoft’s attempt to improve on the lackluster 6.5 release while it readies Windows Mobile 7.

Aspen is part of Sony Ericsson’s GreenHeart line of environmentally friendly smartphones, which are built from recycled plastics and use water-based paints. For this reason, the company describes Aspen as a “business phone with a conscience,” although it’s unclear whether the device is actually sentient and able to discern between right and wrong.

For business users, Aspen features a QWERTY keyboard and offers users the ability to “view and edit office files easily and comfortably,” according to Sony Ericsson. Microsoft’s MyPhone service, which remotely wipes data from devices when they’re lost or stolen, is also part of the package.

Windows Mobile 6.5.3 has been hidden under the same shroud of secrecy that has obscured all of Microsoft’s mobile plans in recent months. Microsoft has been dropping hints about upcoming mobile related news at Mobile World Congress later this month and at MIX10 next month, but it’s anyone’s guess as to whether these will involve Windows Mobile 7.