(Pocket-lint) - The HTC One M8 is nearly a year old. It has been, without a doubt, one of the highlight devices of 2014. It sat at the top of our Best Smartphones chart for a healthy part of the year and has won global acclaim, picking up numerous awards.
There's also no denying that design has been one of the biggest talking points. It wasn't until the emergence of the iPhone 6 that we saw another predominantly metal device hit the market, and we can't help feeling that the HTC One M8 played its part in inspiring, and redefining, what we expect from a smartphone's design.
It's not only about the metal body
But there has always a lot more to the M8 than the casing. The speakers, dubbed BoomSound by HTC, didn't suffer with the departure of Beats Audio.
In fact, those speakers are still the best around and although that might seem like a minor point on the super computer in your pocket, with consumption of media being one of the biggest demands of such devices, great quality speakers are not just the icing on the cake, they're the cherry on top too.
But then we had a gorgeous display and plenty of power packed into a device that was a good size. It wasn't the biggest, but it was a more attractive package than the SGS5, and more manageable than the Xperia Z2. The battery life was surprisingly good too, considering it was a lower capacity than some rivals.
HTC's software, too, has been very slick. It's fast, it's not over-loaded with duplicated functionality (as Samsung is wont to do) and although, at the time of writing, we're still waiting for Lollipop to land, it's been a generally enjoyable UI to live with.
Tripping over the camera
But one area in particular drew criticism; the camera was the sword onto which the M8 fell.
You have to take your hat off to HTC for trying to do something different, and trying to do it twice. First, on the M7, it introduced the UltraPixel sensor; then on M8, the Duo Camera. Neither resonated well with consumers, despite their logical implementation at the time.
Duo Camera, ultimately was dismissed as gimmicky, while UltraPixel has failed to impress against cameras from Apple, Sony, LG and Samsung.
Having used the M8 heavily since its launch, we also noticed wear and tear on these cameras. Some sort of coating that HTC used on them has rubbed away over time, reducing the quality of the cameras, both front and back.
HTC One M9's recipe for success
With the M8 reaching the end of its tenure, all attention turns to the flagship waiting in the wings: the HTC One M9.
Expected to launch on 1 March 2015, we're starting to see design leaks that give us an idea of what's coming and it looks like HTC is playing to its strengths.
With design so widely lauded, sticking to that full metal design is the right thing to do. It's said to be a refinement, slightly smaller than the current M8, but sticking to the same size of display.
In a world where smartphones are expanding towards the unwieldy, giving people slightly less to grapple with is going to be popular.
Sticking to a full HD, 1920 x 1080 pixel display might be lambasted by some, but we think it's right. Some larger displays might benefit from Quad HD, 2560 x 1440 pixels, but at this size, we don't think it's worth the trade off against battery life.
On the software front we'll be seeing Android 5.0 Lollipop and Sense 7. We'd fully expect that to rollout to the M8 too, so it won't be the preserve of the M9 on which is makes its debut.
Naturally there's going to be plenty of power, but it's really the camera where HTC One M9 has to make its case, to right the biggest wrong of the M8.
Duo Camera is gone and in its place will likely be a 20.7-megapixel sensor on the rear, with a dual tone flash. It's simple, but it's a formula that's worked for Sony's devices, and worked well. We'd expect optical image stabilisation and if HTC doesn't offer it, then it shoots itself in the foot despite its efforts.
But the interesting thing is the repurposing of UltraPixel. The recently announced HTC Desire 826 uses UltraPixel as the front camera. This sensor has a lower megapixel count than many smartphone cameras - it's only 4MP - but it has larger pixels at 2 microns.
The theory is that UltraPixel captures light better, so for those low light selfie situations, it should offer better results than a typical 5-megapixel front camera.
Together, the revision of the cameras looks like it could be one of the most important changes that HTC will make to the M9 and it's here that the HTC One really evolves and here that the HTC One M9 will really be judged.