Sony is already looking forward to next year and has already registered two phones with a Russian regulatory body. The Sony Xperia G3121 and G3112 are their internal model numbers, which doesn’t tell us much except to suggest they may be mid-range or even low-end devices.
The Xperia E4 a while back had a number of G2104. Sony’s internal numbers are not terribly consistent though, the two new phones may be closer to the Xperia XA instead, aka “F311x”.
The rumor mill is lacking Xperias currently, but we should see some breaks in secrecy as big tech events approach (CES, MWC). Certainly as more regulators get involved - some of them are nice enough to list the specifications and post photos of the phones they certify.