Sony model names follow a simple scheme the letter indicates the year. For example, H was used for 2018 phones (XZ2, XZ3, XA2, L2), G for 2017 models (XA1, XZ1, etc.) and so on. So, what do you make of this?
The User Agent profiles for three Sony units were discovered J8110, J8170 and J9110 (we think they are the same model, see below). The I generation wasnt skipped over, there are UA profiles for the likes of I4113 (likely XA3) and I4312 (L3).
So, we wouldnt have expected to see J-phones until 2020. And look at that resolution, 1,440 x 2,880px. Thats a pure 16:9 or slightly taller as UA profiles dont always include things line on-screen buttons in the reported resolution.
Even so, the screen is not nearly as tall as the 21:9 CinemaWide panels for the Xperia XZ4. And this is very definitely a flagship device were talking about.
The UA profile of new Sony flagship shows it will run Android 9 Pie
Heres a crash course on Sony model numbers:
The first digit in the model name denotes device class and SIM count 8 is flagship, 9 is dual-SIM flagship, 3 is mid-range, 4 is dual-SIM mid-range.
So, the J9110 is just the dual SIM version of the J8110. The digit is used for different regions/modem versions (e.g. GSM vs. CDMA), so the J8170 should be the same phone again, just for a different market.
Source (in Japanese)