Looks like Sony has a hard time stopping device leaks, there is another leak that hints at an Xperia device with a 4K display. This puts Sony in the spot to be the first manufacturer to release a device with such a high resolution display. The model spotted in the leak has the model number as Sony E68XX(E6833,E6853,E6883) and is expected to be a phone with a huge display
A UAProf(user agent profile) of the handset was found which suggests that the handset may have a display resolution of 3840×2160 pixels. If this is indeed true the device will be the first in the world to have such a high resolution. The same user-agent profile also suggests that the device is running on a Snapdragon 810 processor.
Source- Xperia Blog
The device is rumoured to be the Xperia Z5+ or the Z5 Ultra and in all probability will have a big display. Sony has also started using the Ultra naming recently with the launch of the Xperia C5 Ultra so there is a slim possibility that the Z series gets the Ultra branding back. Even if we assume the phone to come with a 5.5 inch display, with that kind of resolution the phone will be putting out an insane 801PPI of pixel density. I have doubts of such a panel existing. Hence I think the device here in question is a tablet with a 10 inch display and 4K resolution.
Current Xperia Z3+ is using the same 810 processor and it looks like Sony is planning to use processor for the future models as well. Recently the Xperia Z5 and the Xperia Z5 Compact were leaked hinting at a fingerprint scanner in the power button. With IFA 2015 a few weeks away it’ll be interesting to see what Sony has planned all along.