(Pocket-lint) - Some images purporting to be the rear panel of the upcoming Sony Xperia XZ1 have appeared on Chinese site Weibo. The rear panels are distinctly different from the Xperia shells we saw leaked last week, which now transpire to be from the XZ1 Compact.

Note that the naming of the Compact version of the phone has changed from XZ Compact, to XZ1 Compact, so we'll use that from now on.

The rear shell for the XZ1 however, shows no rear-mounted fingerprint sensor. On the Compact shell, there is a rear-mounted sensor. This would imply Sony will integrate the fingerprint scanner into the power button, as it has done on previous flagship devices.

There's a good chance that if Sony does go down that route, then the scanner won't be enabled in the US. Previous Sony devices to have the same function can't be used in the US because it will infringe on a patent owned by Apple. In Europe and other territories, it isn't a problem.

Sony Xperia Ailesi

The lack of fingerprint sensor on the back of the phone is backed up in some other images leaked by Sony Xperia Ailesi, via Phone Arena. The images show what appears to be a final build of the Xperia XZ1. It's definitely a Sony smartphone, using the a similar OmniBalance design we've come to expect from the company.

The edges look slightly curved, and there are large bezels above and below the screen. On the back there's just the camera - expected to be 19-megapixels - and flash, meaning the fingerprint scanner is almost certainly integrated into the power button. 

Specs for the Sony Xperia XZ1 are said to include a Snapdragon 835 processor and a 5.2-inch full HD display with HDR support. You may think a 5.2-inch screen is rather small for a flagship phone, and especially for one that has a Compact variant too.

Well, the Xperia XZ1 Compact is said to come with a 4.6-inch full HD display, as well as the Snapdragon 835 processor. Both phones are expected to receive 4GB of RAM and as for power, the XZ1 should get a 3,000mAh battery and 64GB of storage while the XZ1 Compact will get a 2,800mAh unit instead.

The two XZ1 phones, along with a new X1, are expected to be unveiled at IFA in September, so we don't have long to wait to find out exactly what Sony has planned for its next release of smartphones.

Writing by Max Langridge.