Sony's latest Xperia Z4 may see a global release as the Xperia Z3+, which wouldn't be too surprising considering its specifications compared to the Xperia Z3.

When Sony unveiled its Xperia Z4, allegedly its flagship smartphone for 2015, it was curious to say the least that it did not provide any details regarding a global release. It simply made a quiet announcement in Japan, fueling rumors that the Xperia Z4 may be for the Japanese market only. An intriguing Xperia P2 handset surfaced recently as well, sporting very similar specs to the Xperia Z4, making things even more confusing.

Adding even more fuel to the fire, some new information now hints that the Xperia Z4 may in fact launch globally as the Xperia Z3+. More specifically, the Xperia Blog spotted a white paper on a Sony SCR30 Style Cover Window, noting that the accessory would be compatible with the Xperia Z4/Z3+. Sony has since removed the reference from its website, which further indicates that it may be for real.

Truth be told, the Sony Xperia Z4 recently revealed in Japan doesn't sound like such a big upgrade over its predecessor, so an Xperia Z3+ branding may be more appropriate. Sony has also made incremental upgrades from one flagship to another, from the Xperia Z1 to the Xperia Z2 and the Xperia Z3, at least up until now.

The Xperia Z4, meanwhile, comes with a more powerful Qualcomm Snapdragon 810 processor and a slimmer and lighter body, but otherwise it sports virtually identical specs to the Xperia Z3 albeit for a smaller battery, not a larger unit as one would expect.

The purported Sony Xperia P2, meanwhile, leaked a few days ago with nearly the same specs as the Xperia Z4, i.e. the same 5.2-inch full HD display, the same 64-bit octa-core Qualcomm Snapdragon 810 processor, the same 3GB of RAM and 32GB of internal storage capacity, and the same 5.1-megapixel front camera. On the other hand, the Xperia P2 allegedly features a thicker body compared to the Xperia Z4, a 12.1-megapixel main camera, and a larger 4,240 mAh battery.

With so many confusing leaks and a curious Xperia Z4 launch, it's tough to tell at this point just what will come next. Giving the specs of the Xperia Z4, however, and the fact that it was unveiled only for Japan, there's a chance that Sony may unveil its real flagship later this year, packing some more impressive upgrades over the previous Xperia Z3. Everything is still in the rumor point for now, but we'll keep you up to date as soon as more pertinent information comes to light.