A new Sony Xperia model number has been certified by the UPnP Forum. We haven’t heard of the Xperia ST27 before, but if we were to make a sensible guess we would say that this is the successor to the Xperia active (ST17). There are no specs listed on the product certification but we would imagine this handset to be powered by the same 1GHz dual-core ST-Ericsson NovaThor U8500 chipset as seen in the Xperia P and Xperia U.
We would also expect it to have the same dust and waterproof resistant capabilities of the original Xperia active. Other likely features should include a 3.5-inch (480 x 854) display and 5MP camera. This is all speculation from us though, so you’ll have to sit tight until we hear more.