SINGAPORE — If it ain’t broken, don’t fix it. That must have been HTC’s credo when the Taiwanese manufacturer was working on its successor to one of the most well-liked models of last year, the HTC One M8.

The HTC One M9, launched in Singapore on Saturday, retains every element of charm its predecessor is known for: The downright gorgeous unibody frame, nifty user interface and iconic dual speakers that pack a hefty punch. Meanwhile, inside, the specs got a bump.

The HTC One M9 all-aluminium body is refined with a brushed look on its metallic back panel and a scratch-resistant finish. Its sides are mirror-polished, encasing a vivid 441ppi full HD 1080p 5-inch display. The power button, which has been moved to the right side of the phone, will take a little bit of getting used to. I frequently mistook it for the volume button.

A substantial upgrade is that its speakers now come with Dolby Audio Surround, a multi-channel 5.1 virtual surround system, that makes a movie experience on the phone more immersive and engulfing. Its two front-facing speakers also pack a wallop with a built-in amplifier that delivers 24-bit HD sound — that is 16,777,216 levels of volume. This, however, is probably less useful given that most songs are downloaded in 16-bit format with far less volume gradation. Plus, a 24-bit song will take up about 100MB of space, compared with an MP3 file at about 3MB.

When it comes pictures, its rear camera now packs a 20-megapixel sensor. Pictures have plenty of detail, great contrast and colour vibrancy, although splotches of discolouration are visible under moderately low light. Unfortunately, pictures also lack sharpness and accuracy as it does not come with optical image stabilisation. Its front camera has a wider-angle lens at 26.8mm with HD video capabilities. Video shoots at 4K resolution, a standard that is en vogue in the film industry. Details, colours and contrast are great, but the video’s graininess — noisy pixels that dance about — is jarring.

Inside, the HTC One M9 is packed to the rafters with an upgrade of the latest processing gear from Qualcomm — the Octa-core Snapdragon 810 — 3GB of RAM and the HTC Sense 7 user interface, on top of the Android 5.0 Lollipop operating system (OS). It even has a built-in universal remote control that allows you to use your phone to control your cable box or television.

This new version of Sense seems flatter in interface design, with the removal of unnecessary stylistic elements that could lap up battery life. In fact, the M9 comes with a larger 2,840mAh battery, and should outlast the M8’s 2,600 mAh battery, but online reviews have suggested that they came out on almost equal footing. We suspect its big Octa-core processor is what’s taking up more power. After about 12 hours of moderate use, I had about 30 per cent battery life left.

Navigating on the M9 is snappy, helped by the more responsive Lollipop OS. HTC added some new features such as custom widgets that change the apps that show up based on your location. You first key in your most frequented locations, such as your home and workplace. At work, the landing screen showed me apps such as Mail, Calendar and Scribble — a note-taking app. On-the-go, it switched to apps such as Maps and Music. At home, it prioritised apps such as Play Store and Calendar. Though a welcomed feature that can make the smartphone truly smart, customisations were not easy. I could not add or subtract apps shown under these location modes.

Overall, the M9 is a good phone that will satisfy most users. But with mostly just incremental improvements and a price tag of S$1,008, the M9 will face tough competition from the likes of Samsung’s Galaxy S6. The HTC One M9 is now available in dual-tone silver and rose gold, and single-tone gunmetal grey, at M1, Singtel and StarHub stores.