Sony has officially announced the successor to its flagship Xperia Z3 smartphone - which will be known as the Xperia Z3+ everywhere except Japan, where it was very quietly released previously as the Xperia Z4.

Same device, different name, and while this won't come as too much of a shock to anyone who was following the rumours and speculation, it does beg the question as to why Sony didn't just call it the Xperia Z4 worldwide.

Naming confusion aside, the Xperia Z3+ has been unveiled and we got our hands on it to give you our first impressions on what the latest flagship brings, how it differs from its predecessor and why the name isn't such a bad decision. Sometimes it's the little things that make all the difference, so put any expectations aside, keep an open mind and say hello to the Xperia Z3+.

First up: why the different name? Sony has said the main reason for the difference is down to Sony's dominance of the Japanese market, where consumers "crave flagship devices with the latest features as soon as they can be delivered".

Sony told us the Xperia Z3 flagship was still performing well in the rest of the world and therefore the purpose of the Xperia Z3+ is to act as "a premium addition to the existing flagship series" to address customers that would like to have the latest features and refinements.

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Essentially what Sony has done here is what Apple does every other year with its 's' iPhone model. It has refined its flagship device rather than given it a complete design overhaul.

Xperia Z4 suggests a new all-singing and all-dancing flagship - like the Galaxy S6 and S6 edge for Samsung - but that's not what the Xperia Z3+ is about. Instead it sticks with the attributes of the Xperia Z3 and improves it to bring a name that is far more representative of what you get, rather than set itself up for too much expectation.

At first glance, the Xperia Z3+ and the Xperia Z3 look almost identical. In fact, if one hadn't of been black and the other green, it would have been very hard to tell them apart quickly. But make no mistake, there are differences in the two handsets and they are differences that matter.

The most notable change is the open Micro-USB port [do happy dance here], with Sony finally removing the flap that made charging awkward on the Xperia Z1, Z2 and Z3. The Xperia Z3+ is still waterproof and dustproof like its predecessors, it's just far less fiddly when it comes to charging. We first saw the capless Micro-USB port arrive on the mid-range Xperia M4 Aqua back in February and we loved it, so it is a welcomed addition to the Z series.

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The Xperia Z3+ features the charging port in the centre of the bottom of the device, like you find on the Apple iPhone 6 for example, rather than right at the top in the corner like on the M4 Aqua. Its positioning didn't bother us on the M4 Aqua but seeing it move to the middle at the bottom on the new device makes a lot more sense.

The signature side power button sits firmly in place on the right of the Xperia Z3+ but the microSD slot has moved to the opposite side. This means the power button is only accompanied by the dedicated camera button and the volume rocker, delivering a more refined and fuss-free approach compared to the Xperia Z3.

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On the left-hand side where the microSD slot relocated, you'll find the microSD writing removed, and the SIM slot in the same place. There is also no longer any need for the two-pin dock connector with the the open Micro-USB port so you get a much more seamless finish on this side too.

The Xperia Z3+ is the slimmest Z series device so far at 6.9mm, and it weighs just 144g. We might only be talking a matter of millimetres and grams difference compared to the 7.3mm thickness and 152g weight of the Xperia Z3, but it's noticeable. We were pleasantly surprised when we picked the two devices up together as the Xperia Z3+ really did look and feel beautifully slim and light. It was a delight to hold, just as the Xperia Z3 is, but the diet worked wonders for the Xperia Z3+ and it's a lovely device.

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The rear and front remain identical to the Xperia Z3 so you'd find it difficult to tell the difference between the two face on. The NFC tag still sits above the centralised Sony logo on the rear, and the bezel surrounding the display is still a little on the thick side on the front. You'll also find the front facing speakers in the same place, but Sony has added a couple more audio technologies to the growing list, with the addition of LDAC and AHC. LDAC means you can listen to top quality tracks wirelessly and AHC stands for automatic headset compensation to give you personalised sound. We couldn't test these during our hands-on time, but generally speaking, the volume seemed good and clear.

All-in-all, the OmniBalance design we have come to expect from Sony is still very much present with the aluminium frame, rounded corners and tempered glass rear and front finishes that love a fingerprint are very much intact. You get the same well-built and premium quality feeling with the Xperia Z3+ as the Xperia Z3, but everything is just that little more polished.

There may have been rumours suggesting a QHD display for the Xperia Z4, but that wasn't the case for Japan or for the rest of the world as the Xperia Z3+ has the same 5.2-inch 1920 x 1080 pixel resolution screen as the Xperia Z3. This means a pixel density of 424ppi, which may not come close to the likes of the LG G4 and its 534ppi, or the Galaxy S6 and its 577ppi, but the Xperia Z3+ has a good display nonetheless.

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We don't tend to pass judgement on displays when we first see them as we prefer to use them in the real world first, but we thought the Xperia Z3's display was good and it seems you'll get exactly the same experience with this new handset. Viewing angles were reasonable and while there was still a bit of dimming when we viewed it at an angle, the improvement from the earlier Z devices is apparent yet again.

The brightness is fantastic as it was on the Xperia Z3 and you get lovely vibrant and punchy colours on the Xperia Z3+, which were a pleasure to look at. We will wait until we come to review the Xperia Z3+ to pass final judgement, but from what we could tell during our brief time with it, we shouldn't have too many complaints.

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It would have been nice to see a QHD resolution introduced on this model so Sony could keep up with its competition, but perhaps we will see it on the next flagship instead.

The camera has always been one of Sony's biggest marketing points when it comes to its smartphones and so it will come as no surprise that the 20.7-megapixel rear camera has made another appearance. It has been improved slightly since it first appeared on the Xperia Z1 however, with the Xperia Z3+ offering the same 25mm wide angle lens and maximum ISO 12,800 sensitivity as the Xperia Z3.

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There is a slight improvement when it comes to the front camera on the Xperia Z3+ compared to the Xperia Z3 however, moving from 2.1-megapixels to 5-megapixels and Sony has also introduced new software elements.

Superior Auto mode now recognises up to 52 difference scenarios that are made up of 13 scenes and four modes to adapt the settings automatically. One of these modes includes Gourmet Mode, which is said to make food shots look "better than ever" so if you are one of those people who takes a picture of every meal before consuming it, this might please you greatly.

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Superior Auto is also being introduced to the front camera for the Xperia Z3+ and SteadyShot and Intelligent Active modes will also be present on the front. The new device will also see more apps introduced to the Smart Social Camera functionality, including Style Portrait and AR Mask.

We didn't get a chance to test the camera during our hands-on time with the Xperia Z3+, but we would expect similar results to the Xperia Z3 when we come to review it, with hopefully better selfies now that the front camera has seen a boost.

The Xperia Z3+ runs on the latest 64-bit coat-core Qualcomm Snapdragon 810 processor, which neither LG or Samsung opted for with their latest flagships. It's a big step up from the Xperia Z3's Snapdragon 801 chip and we thought the Xperia Z3+ was notably slick when we were flicking through various tasks. The camera took a little longer than we would have liked to launch but the model we saw wasn't final software so we suspect this will get ironed out come launch.

The Xperia Z3+ will have a 2-day battery life according to Sony, and while a full 48 hours may be pushing it, we would be willing to bet you'll get at least 24 hours as Sony is known for devices with a decent amount of juice to see you through.

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The new device will come with a quick charge accessory too, which Sony claims will give you 1 day usage for 45 minutes charging. We will have to wait and see how well the battery performs when we come to review the Xperia Z3+, but we have high hopes given the updated processor and Sony's software.

Speaking of software, there have been a few changes in the Xperia Z3+ aside from the camera additions. The settings menu has changed slightly from the Xperia Z3, delivering a much more refined approach. We didn't get a chance to work through all the various software elements, but we will look at the changes in more detail when we come to our full review.

If you see the Xperia Z3+ for what it is, you're looking at another beautiful smartphone that takes everything its predecessor did right and sticks with it, while refining and improving the areas it fell down in. If you see it as Sony's next flagship with hopes for a complete design change or significant differences, you'll be disappointed.

The Xperia Z3+ is all about managing expectations and this is where Sony has hit the nail on the head by calling it the Z3+ instead of the Z4. It's not worthy of the Z4 name as the differences aren't radical enough, but it is worthy of existence as it offers some great improvements to deliver another lovely Z-series smartphone.

The removal of the Micro-USB port cap is a true blessing, while the other design refinements including the reduction in thickness and weight and the more fuss-free approach are welcomed additions. Couple that with the increase in front-facing camera megapixels, software enhancements and processor upgrade and you have yourself what seems to be a great device.

The Xperia Z3 was a fantastic smartphone and while Sony has some tough competition on its hands, especially with LG making some big moves in the camera department on its G4, the Xperia Z3+ makes enough simple improvements to keep Sony ticking along.

Some may be disappointed, some underwhelmed, but the Xperia Z3+ is all about the little things, and sometimes it's the little things that count.