HTC was one of the first to launch a flagship Android smartphone last year and as testament of how good the One M8 was, it still made the list of the best Android phones in the market by year's end.

The new HTC One M9 is now official and it's not a radical redesign but an evolutionary refinement of the same metal unibody formula, boasting of a thinner profile and improved camera (One M8's lowest point) running on top of Android 5.0 Lollipop.

Announced at Mobile World Congress, the One M9 is powered by a Snapdragon 810 octa-core SoC running at 2GHz, 3GB RAM, 32/64GB of internal storage expandable via microSD, and the same BoomSound speakers that people loved in the previous-gen One. The 4 megapixel 'UltraPixel' camera has been replaced by a 20-megapixel rear facing camera that slightly protrudes on the back.

The new HTC One M9 is not a radical redesign but an evolutionary refinement of the same metal unibody formula

The shape of the M9 is seemingly identical to the M8, but upon closer inspection it's been made easier to grip, has sharper edges, and the back is not as slippery as before. The power button has been relocated to the side which is arguably the better placement for a large 5-inch handset.

The One M9 keeps the display at 5 inches and 1080p resolution, quite possibly a good thing if you want a balanced smartphone. HTC has managed to fit a slightly larger battery rated at 2,840 mAh with support for Quick Charging.

Android 5.0 has been customized with HTC Sense 7, and while generally these OS modifications add more inconsistency than anything else to Android, Sense 7 has been favored so far by those who have briefly used the phone for its lack of bloat and added personalization.

HTC also announced some accesories for the new M9. A second generation Dot View case that combines a cover with clever through-the-case notifications. The M9 is not waterproof out of the box but an IP68 water resistant Active Case and Active Headset will also be available for purchase.

The new HTC One will be available in the U.S. from all four major carriers and other retailers by the end of March. No official word on pricing yet, but a leak from Best Buy earlier today suggested the One M9 would cost $649.99 off-contract, which would put it at $199 from a carrier with a two-year commitment.