Sony has officially unveiled a "premium" Xperia Z3+ smartphone, which is simply the global version of the Xperia Z4 announced for Japan.

When Sony quietly announced its new-generation Xperia Z4 in Japan last month, it raised more eyebrows than interest. First of all, the Xperia Z4 didn't come with the great improvements everyone expected over the previous Xperia Z3. Second of all, the handset seemed exclusive to Japan, as the company made no mention of its availability in other markets worldwide.

Some references spotted on Sony's website later indicated that the Sony Xperia Z4 would see a global release as the Xperia Z3+, and the rebranding seemed appropriate considering the iterative upgrades compared to its Xperia Z3 predecessor.

It now seems that the Sony Xperia Z4 is indeed launching globally as the Xperia Z3+, as the company just made it official. The newly-announced Xperia Z3+ is not a phablet as the name might suggest. The smartphone comes with a 5.2-inch full HD display with a resolution of 1920 x 1080 pixels, i.e. the same screen of the Xperia Z3 launched last year. The design is quite similar as well, albeit the new iteration is a bit thinner and lighter.

Under the hood, the Xperia Z3+ comes with a 64-bit octa-core Qualcomm Snapdragon 810 processor, an Adreno 430 graphics processing unit (GPU), and 3GB of RAM for a fast and fluid performance. The handset also sports the same 20.7-megapixel rear camera of its predecessor, but replaces the 2.2-megapixel front shooter of the Xperia Z3 with a more powerful 5-megapixel selfie cam. Sony has also equipped both the front and the rear cameras of its new Xperia Z3+ with mobile image sensors, which should translate to better images in low-light conditions. LTE Cat. 6 and Wi-Fi MIMO support should allow for faster connection speeds, while the smartphone's battery will reportedly last for two days on a single charge, according to Sony. The Xperia Z3+ is also waterproof and dust-resistant, just like most recent smartphones from Sony.

"Slimmer (6.9mm), lighter (144g) and expertly crafted, Xperia Z3+ continues the Sony design story with discreet, but impressive improvements. Not only is it waterproof and dust-tight (IP65/68) ideal for use in all situations, as a further design refinement Z3+ features a capless USB port making it easier and more convenient to charge your phone," Sony boasts in the press release on Tuesday, May 26.

"In addition the magnetic charging pin has been removed, resulting in an overall more seamless and minimalist design. With a shiny finish on the metal frames, tempered glass and rounded edges, Xperia Z3+ is beautiful to look at from any angle and comfortable to hold."

The Sony Xperia Z3+ will also come in "sophisticated" color options, adding Copper and Aqua Green to the classic Black and White avatars. The handset is set to go on sale this summer, but no specific launch or pricing details are available at this point.

For more information about the specs of the new Sony Xperia Z3+, head over to the product page at this link. To get a better look at the smartphone, check out the video below.