As far as we know, HTC’s 2015 roadmap should include, first and foremost, a successor to the One (M8). Currently codenamed HTC Hima, this successor seemingly sports a 5-inch 1080p display - so no changes here - while featuring a 64-bit Snapdragon 810 processor, 3 GB of RAM, 20 MP rear camera, and a 13 MP front-facing camera. Android 5.0 Lollipop with Sense 7 UI should be on board. Obviously, these are unconfirmed features. A Hima Ultra variant, possibly sporting a 5.5-inch display with a higher pixel resolution (Quad HD?) may also be in the cards.
A new generation of HTC Desire smartphones will be introduced next year as well. The first new Desire models are expected to be announced next week at CES 2015. But it’s unlikely that we’ll see the HTC Hima then, as it’s been recently suggested.