I suppose you have to give Sony credit for at least keeping its customers informed. Today, the manufacturer announced an update to its plans for bringing its phones up to Jelly Bean. If you're rocking the Xperia T, Xperia TX, or Xperia V, you should see Android 4.1 "during February and March." Of course, this will depend on what market you're in or which variant you own.
Following those flagships, the Xperia P, Xperia J and Xperia go will start to receive their upgrades starting around the end of March. Following that release, the Xperia S, Xperia SL, Xperia ion and the Xperia acro S will be updated "in the subsequent weeks." Of course, schedules are always subject to change, but all of this information lines up pretty well with what we've heard before from the company.