HTC left the One M9 alone to bathe in limelight of the MWC, but it has a second slightly bigger device on the way. The HTC One M9+ will have a 5.2" screen allegedly and all indications are that it will be HTC's first QHD display (1,440 x 2,560px).
The One series hasn’t had the slimmest bezels recently and in seems that the One M9+ will not be a tiny device either. The handset is rumored to measure 150.9 x 72.5 x 10.2mm, compared to 144.6 x 69.7 x 9.6mm for the base One M9.
Another comparison will be with the LG G2 and it's 5.2" screen, the tiny bezels around it make it only 138.5 x 70.9 x 8.9mm. Of course, it doesn’t have stereo speakers on the front, which do add some bulk. The Sony Xperia Z3 (also 5.2" screen and stereo speakers) is 146 x 72 x 7.3mm.
The HTC One M9+ rumors also promise a fingerprint reader, though leaked photos doesn’t show any such thing on the back, so that probably also goes on the front.
Other specs include a MediaTek MT6795 or Snapdragon 810 chipset (region dependent), 3GB of RAM, 32GB of built-in storage and the same 20MP camera as the regular One M9.