The company which supposedly designed and built the new dual-camera system coming in the HTC M8 demonstrated the technology at Mobile World Congress recently. This new camera tech was designed by Qualcomm and Corephotonics and will apparently include a number of advanced features designed to improve pictures taken with the next HTC One (or any phone which uses the tech).
The two-camera system allows for a feature called Computational Photography Zoom which can offer better creativity options to the end user. Primarily, this new advancement allows the device to achieve an optical zoom which is 5x greater than the typical 3x zoom. To be clear, the company, Corephotonics, didn't officially state that their tech will be what is present in the new HTC One, but according to the source of this story, their "coyness" when the right questions were posed indicated it is a very strong likelihood. (Sometimes what you don't say speaks volumes.)
At any rate, the new camera tech doesn't just include this new zooming capability, it also includes the ability to create depth of field effects and can even change that afterwards. The next iteration of the HTC One (aka the M8) is due to be launched on March 25th.
Source: Pocket-Lint