A pic of the Sony ST25i Kumquat leaked online last Friday – seems to be the little brother to the Xperia S as it’s rumoured to come with the same overall design, but with a 3.5-inch display, 1GHz dual-core processor and 5MP camera. However, as much as the Kumquat is a striking name, a new filing shows that the official go-to-market name might end up being known as the “Sony Xperia U”. This is what has shown up at Postel, the Indonesian equivalent of the FCC in the United States. No other details are given, or if this is the name that will be used globally. Surely more details will come closer to Mobile World Congress next month.