The X Performance is everything that the Z6 is likely to have been. It's got a new, supposedly improved camera, the latest Qualcomm Snapdragon 820 processor, 3GB of RAM, and Android 6.0 Marshmallow. It's a flagship. The one area it falls short in comparison to, for example, Samsung and LG's latest, is display: its got what appears to be the same 5-inch 1080p display that graced both the Z3 and the Z5.

Although all three are unmistakably Sony phones, there is a small shift in design with the new series. It's a more rounded look than we've seen from Sony before, with a smooth curve where the back meets the sides. This effect is mirrored by the curved glass of the display. It's not the design revolution that you'd expect from a device that splits from the Z nomenclature, but it is... different?

Sony had been on a rapid upgrade cycle until recently -- the Z was announced in January 2013, and by September 2015 it had been directly superseded by the Z1, Z2, Z3, Z3+ and Z5. That's an average of one flagship for every six months. Whether it'll slow down this upgrade rhythm with the X series won't be clear probably until this time the next MWC, but you can almost certainly expect some smaller and larger X smartphones sometime this year.