The Sony Xperia Z4 smartphone is coming to the UK under the guise of Xperia Z3+, and you can pre-order it today. Here are all the details on the Sony Xperia Z3+ UK release date, price, specifications and new features. Also see Best smartphones 2015 and Best Android phones 2015.

Update 12 June: The Xperia Z3+ is now up for pre-order and will go on sale beginning 15 June. See more details below.

Although the name suggests the device is merely a tweaked version of the Xperia Z3, which it is, the fact the almost identical Xperia Z4 has been announced for Japan. It's quite a confusing message from Sony and leaves us wondering whether there will be a properly new generation of flagship this year at all.

The firm does admit that this is an 'evolution to the Xperia Z3 family' claiming that it's called the Z4 in Japan because "consumers there crave flagship devices with the latest features as soon as they can be delivered". Meanwhile, the Z3+ is 'premium addition' to the existing range. Also see: Google I/O live stream, live blog.

Read our Sony Xperia Z3+ hands-on review.

Sony Xperia Z3+ UK release date and price: When is the Sony Xperia Z3+ coming out? Pre-order the Sony Xperia Z3+

The Z3+ has arrived later than expected after the firm happily stated it was comfortable with a six month refresh cycle (half that of most smartphone makers). That placed the Xperia Z3's successor for an MWC 2015 launch in Barcelona but we got the Xperia Z4 Tablet and Xperia M4 Aqua instead.

Whatever is going on behind the scenes with Sony's launch decisions, the Xperia Z3+ is what we've got and it will arrive in June.

Update: Carphone Warehouse is now accepting pre-orders for the Xperia Z3+ which will be available on 15 June and it has the exclusive on the Ice Green colour. You can get it starting at £31.99 per month with a £59.99 upfront cost. Those who pre-order will get a free High-Res audio bundle which includes a pair of HQ audio MDR10-RC Sony headphones, 90 days free music streaming on in-demand site Tidal and six Hi-Res audio albums. The Xperia Z3+ will be available in-store from 26 June.

Sony hasn't announced pricing, stating merely that "pricing will reflect the premium quality of the phone", but Mobile Fun and Clove are already taking pre-orders at £549 for the Black and White Sony Xperia Z3+. Mobile Fun is also offering a free tempered glass Olixar screen protector worth £12.99.

Sony Xperia Z3+ software

Sony Xperia Z3+ specs and new features

Much is the same when comparing the Xperia Z3+ to the flagship Xperia Z3. It still looks pretty much the same and has a 5.2in Full HD screen. The 20.7Mp camera remains, as does 3GB of RAM, 32GB of storage and a microSD card slot.

So what's changed? Well the device is thinner and lighter at 6.9mm (Sony says it's the thinnest flagship Z device) and 144g and the waterproofing is still a key feature but the Micro USB is now capless making charging a lot easier. As a side note, the metal contacts normally found on the side for use with a docking station are now gone.

The main change hardware wise is a jump from a Qualcomm Snapdragon 801 processor to the newer Snapdragon 810 – which other vendors such as Samsung have shunned. This is a 64-bit octa-core chip with four A53 cores at 1.5GHz and four A57 cores at 2GHz. See: What's the fastest smartphone 2015?

Although the camera is still 20.7Mp, Sony said Superior auto now recognises up to 52 different scenarios and there's a new Gourmet mode especially for those snaps of your posh nosh. The Superior auto mode SteadyShot with Intelligent Active Mode is now available on the front camera, too.

In the audio department, Sony has added an LDAC (the ability to enjoy top quality tracks wirelessly) and AHC (Automatic Headset Compensation, providing personalised sound).

The battery in the Xperia Z3+ is smaller than the Z3 at 2900mAh (down from 3100mAh) but Sony still says that the device will last two days. The new quick charge accessory (not included) will supposedly give you a day of usage from just 45 minutes charging. There's no wireless charging here.

Sony Xperia Z3+ full specifications:

•    Operating system: Android 5.0 Lollipop
•    Display: 5.2in Full HD (1080 x 1920), 428ppi
•    Processor: Qualcomm Snapdragon 810, 64-bit, octa-core
•    Memory: 3GB RAM
•    Storage: 32GB internal, microSD card slot (up to 128GB)
•    Cameras: 20.7Mp rear, 5Mp front
•    Connectivity: LTE Cat 6, Wi-Fi, Bluetooth, GPS, NFC
•    Battery: 2900mAh non-removable
•    Dimensions: 14 x 72 x 6.9mm, 144g
•    Colours: Black, White, Copper, Ice Green
•    SIM: Nano SIM