According to SamMobile blog the next Galaxy S device is Galaxy S IV and it is under development and it may launch in April 2013.
According to the blog Samsung Galaxy S IV will have bigger and better display, a 4.99-inch Super AMOLED display with 1920*1080 resolution, pixel density of 441PPI, 13-megapixel camera power, a significant upgrade over the Galaxy S III’s 8-megapixel rear shooter, 2 GHz quad-core Exynos processor and an 8-core GPU.

“Looking to the first half of 2013, we see evidence of Samsung likely accelerating the release of the Galaxy S IV – compared with May (this year) for the Galaxy S III,” said UBS analyst Nicolas Gaudois. “We believe preparations for volume manufacturing of unbreakable plastic substrate displays continue. All in all, we could see a strong products push in the high-end in the first half, followed by other releases.”

Samsung declined to comment.

“Eventually, they’ll have unbreakable and flexible displays. Either the Galaxy S IV or S V will have unbreakable and even possibly flexible and foldable displays by 2014. That’s going to be a game-changer,” said Mark Newman, an analyst at Stanford Bernstein in Hong Kong.

Newman and Gaudois both are ranked as 5-star analysts, the top ranking, by Thomson Reuters StarMine for their recommendations on Samsung.

The Galaxy S2 had an amazing Super AMOLED Plus display – and boy, was it vibrant. The S3 upped the screen size from 4.3-inches to 4.8-inches and the pixel density went from 217 to 306 to take a run at the iPhone’s Retina Display. But, Samsung also opted for a PenTile approach, to the chagrin of geeks. What does that mean for the end user?

Well, the screen looks great but you can make out pixels if you really, really strain. And some of the vivacity and colour saturation is lost. On the plus side, Samsung reckons the screen will last longer – but we’d rather see a much more S2-like screen with a sharper resolution – and given that’s now appeared on the Samsung Galaxy Note 2, we’re pretty hopeful we’ll get it on the Samsung Galaxy S4 too.

Alternatively, there have been a number of rumours that Samsung is going to bring a flexible screen to the Galaxy S4 – but given the Korean brand is already pushing the delivery of such tech back into 2013 for its customers, we think we’ll be in Galaxy S5 territory before that happens.

There seems a much more likely option in the shape of the 5-inch 1080p screen that could offer up an eye-splitting 441ppi, making it easily the highest res out there. It would probably need to be shrunk down a smidge to fit into the palm, or Samsung could actually just make the phone even closer to the edges of the screen. Dare we dream of an edge-to-edge display like on the 9000 series TVs?

The S2’s 1,650mAh was manageable and the S3’s 2,100mAh blows that out of the water. But it’s still only OK.