Sony Xperia Z3-20

Sony's next-generation Xperia Z4 could make a somewhat surprise appearance at Mobile World Congress next month after three versions of the device were recently certified in Japan.

In recent years, Sony has been sticking to a 6-month release cycle for its flagship Xperia Z lineup, but its most recent Xperia Z3 only arrived four months ago at IFA 2014 in Berlin. We weren't expecting to see the Xperia Z4 next month, then, but Sony may just surprise us.

We've already seen a bunch of Xperia Z4 leaks, which have given us an idea of its specifications and design. When you combine those with the recent certification in Japan, it would appear that the device is right around the corner. If it doesn't show its face at MWC, it could arrive soon after.

Sony hasn't yet sent out invitations to an MWC event — unlike HTC — but there's still plenty of time for that yet.

The three Xperia Z4 variants that have been certified come with the PM-0792-BV, PM-0793-BV, and PM-0794-BV model numbers, and they're thought to be headed to the three major carriers in Japan — NTT Docomo, au/KIDDI, and SoftBank.

Unfortunately, the handset's specifics aren't disclosed, but recent rumors have suggested we could see big improvements to the Xperia Z smartphone this year. While it's likely to look a lot like its predecessors, the Xperia Z4 is expected to come with a 5.5-inch Quad HD display, a 64-bit Snapdragon 810 processor, and 4GB of RAM.

Other features could include a built-in amp for louder speakers with improved sound, and at least 32GB of internal storage.