HTC's Butterfly series is an interesting one. While this particular range of models rarely makes its way outside of Asia, HTC often uses it as a testbed for new technology and features, and some of the highlights of these phones make it into the primary international lines on the next go-round. The latest version of the J Butterfly, which will launch exclusively on Japanese carrier KDDI next month, has some additions to the basic One design that might be worth watching.
First of all, the body is designed differently, with what looks like high-quality polycarbonate (read: plastic, but nice plastic) instead of the metal we've become used to with the One family. That comes with two advantages: one, the screen design does away with the metal "double bezel" that's been standard since the original One, and two, the J Butterfly is water-resistant to IPX7 specifications. If you look closely, you can see that the dual front-facing speakers are still present.
The other big design change is the Duo camera. Where the One M8 uses a "4-ultrapixel sensor" and a standard 2MP sensor in a dual configuration, the J Butterfly swaps out the main sensor for a more conventional 13MP camera. Since the ultrapixel camera got lackluster results for the last two years running, that might be preferable for some customers. Then again, this might just be a cost-saving measure.
The rest of the phone shares its specs with the One M8 for the most part, including a 5-inch 1080p screen, a Snapdragon 801 processor, 2GB of RAM, and a 5-megapixel front-facing camera. The J Butterfly will also get its own Dot View case.