Sony has announced the Xperia Z4 Tablet at Mobile World Congress in Barcelona, succeeding the Xperia Z2 Tablet that launched at last year's show with the same size display but a reduction in footprint.

The Xperia Z4 Tablet makes numerous improvements over its predecessor to become the "world's lightest and slimmest 10-inch tablet" but how much has changed in terms of the specs and is it enough to splash some cash on an upgrade?

The Xperia Z4 Tablet measures 254 x 167 x 6.1mm compared to the Xperia Z2 Tablet that comes in at 266 x 172 x 6.4mm, meaning the new model is not only slimmer, but its overall footprint has been noticeably reduced.

The Xperia Z4 Tablet takes its design cues from the Xperia Z3 Tablet Compact that was launched at IFA back in September 2014, bringing smooth, curved rounded edges, polished corners and a matte back. It resembles the Xperia Z3 smartphone, while the Xperia Z2 Tablet resembled the Xperia Z2 smartphone so there is quite a big difference in terms of looks.

Weight has been reduced for the Xperia Z4 Tablet too, hitting the scales at 393g compared to the Z2 Tablet's 439g so you lose over 40 grams straight away, resulting in a very light 10.1-inch tablet. Both models are IP55 and IP58 waterproof and dust resistant but the Xperia Z4 Tablet has done away with the flap covering the Micro-USB port to make for more accessible charging.

The Xperia Z4 Tablet comes with a 2560 x 1600 pixel resolution across its 10.1-inch display, while the Xperia Z2 featured a 1920 x 1200 pixel resolution. This means the new model offers a pixel density of 299ppi, compared to the Xperia Z2 Tablet's 224ppi, so in theory you get a sharper, crisper display on the Xperia Z4 Tablet.

Sony has also increased the brightness on the Xperia Z4 Tablet to deliver "the brightest 2K display" but while that is difficult to verify without performing a tablet line up, we could see the difference between the Xperia Z4 Tablet and the Xperia Z2 Tablet when we saw them side-by-side.

Aside from the resolution and brightness however, one of the immediately obvious differences between the Xperia Z4 Tablet and the older Xperia Z2 Tablet when it comes to the display is the reduction in bezel. The Xperia Z4 fits the same size display in a smaller footprint which was only possible thanks to the smaller bezel and the new model looks much better for it.

Sony has pushed the camera on its Xperia Z smartphones since the launch of the Xperia Z1 and now it looks like it is time for the tablets to get their fair share of camera love. The Xperia Z4 Tablet features an 8-megapixel rear camera and 5-megapixel front camera, compared to the 8-megapixel rear snapper and 2.2-megapixel front snapper on the Xperia Z2 Tablet.

There might not be a change in the rear camera but Sony has introduced a wide-angle lens to the front of the Xperia Z4 Tablet camera to improve selfies and video calling over the Xperia Z2 Tablet.

The camera software on the Xperia Z4 Tablet will also provide a little bit extra over the Xperia Z2 Tablet, with all of the Xperia Z3 smartphones camera features being made available on the new tablet. Features including Superior Auto that adjusts all the settings for the best possible picture, along with AR Fun that allows you to add random things to your images such as dinosaurs will be available on both the front and rear cameras of the Xperia Z4 Tablet. Previously these features were only available on the rear camera.

In terms of processor, as you would expect the Xperia Z4 Tablet will be faster than the Xperia Z2 Tablet, featuring the latest Qualcomm Snapdragon 810 chipset in comparison to the Qualcomm Snapdragon 801. The Xperia Z4 Tablet's processor is octa-core while the Xperia Z2 Tablet's is quad-core meaning the new device should be able to handle harder tasks more efficiently.

Both tablets offer 3GB of RAM so there is no change in that department but the Xperia Z4 Tablet will have 32GB of internal memory rather than the 16GB found on the Xperia Z2 Tablet, although both are expandable via microSD.

A 6000mAh battery capacity is found on both the Xperia Z4 Tablet and the Xperia Z2 Tablet, which Sony claims delivers up to 188 hours of music play.

The Xperia Z4 Tablet will launch with the latest version of Android - 5.0 Lollipop - and while the Xperia Z2 Tablet will eventually get the software update, it hasn't yet. 

The software will be pretty much the same once the update arrives for the Xperia Z2 Tablet however, and this will probably mean that both devices will end up with Sony's unique software features too, such as Remote Play.

Remote Play launched on the Xperia Z3 smartphone back in September, allowing users to play their PlayStation 4 on their smartphone. Sony said it would be coming to older devices, which we assume includes the Xperia Z2 Tablet but you can be sure it will definitely be on the Xperia Z4 Tablet.

The Xperia Z4 Tablet is the all-round better device, but this was to be expected. The design, display and processor have all seen improvements, along with an upgraded front-facing camera and more internal storage, which is great for those who use their tablet for gaming.

A few things remain the same including the RAM, rear facing camera and the battery, but overall, you get a lighter, slimmer and better device with the Xperia Z4 Tablet.