Editor's note: We got hands on with a pre-production Sony Xperia Z3+ which wasn't running final software. While the look of the handset won't change, there may be minor cosmetic tweaks before it goes on sale.The Sony Xperia Z4 is here! No, that isn't a typo - I really did mean to type Z4. For this is the Xperia Z4, but as it's the international version of the handset I'm having to call it the Sony Xperia Z3+.Sony Xperia Z3 Plus is a much better name for this handset, as it represents only a very small incremental upgrade from the Xperia Z3 which launched around eight months before.Sony has slightly tweaked the design, upgraded the power and given the front facing camera a bump, while the battery has been reduced in size along with the handset's weight.What the Xperia Z3+ does represent however is a fresh attack on the flagship smartphone market, allowing Sony to stay relevant in a market which now boasts the Samsung Galaxy S6, HTC One M9 and LG G4 along with the iPhone 6.The Sony Xperia Z3 Plus release date is set for June 2015, although I'm still waiting to hear how much it'll set you back. Going by the Xperia Z3 though this won't be a cheap handset - one look at its competition tells you pretty much all you need to know.