Sony’s 2013 product portfolio is a hodgepodge of letters that doesn’t really make sense to anyone, but if you focus on the company’s flagship devices, then things start looking a little bit clearer. At the start of the year, there was the Xperia Z and the Xperia ZL. Same phone, for all intents and purposes, except one was made of glass while the other was made of plastic. Then there was the Z1 and Z Ultra. The former was an update to the Z featuring a better camera and faster chip. The latter was a 6.44 inch phablet.

Last month, in Japan, Sony announced the Z1F, which has the exact same specs as the Z1, except that the 5.0 inch 1080p screen was replaced with a 4.3 inch 720p panel. For the longest time, people have thought that the Z1s would be the name of the international Z1F, but now that’s come into question. According to Xperia Blog, it looks like the Z1s will be an updated version of the Z1. They make this claim because they have a photo (above) of both devices, with the Z1s clearly having a headphone jack in the middle of the device, whereas the Z1 has it on the side.

So what exactly is Sony planning on putting inside the Z1s? That’s the million dollar question. The folks at Xperia Blog have a theory that the Z1s will have a 5.2 to 5.3 inch screen compared to the Z1’s 5.0 inch screen. Looking at the LG G2 and the rumors about the Samsung Galaxy S5, that slight increase in screen size doesn’t sound crazy. As for any under the hood tweaks, those aren’t yet known.