The next photo module iPhone 6S is the object of all attentions and many rumors are associated with it. If those of a double photo module, like the system Duo Camera of HTC One M8, seem to be moving away, the presence of a photo sensor going from 8 megapixels (as on the iPhone 6 and 6 Plus) to 12 megapixels comes back regularly.
She stays alive in Feng.com which further claims that it will be a photo sensor supplied by Sony. This module would use technology RGBW (as on the Huawei P8, for example) which adds a white sub-pixel to the three sub-pixels of the primary colors.
This could help maintain good performance in poor light conditions all using more compact pixels than those of the module iSight 8 megapixels of the current iPhone 6.
Apple would even have intended to initially integrate an RGBW photo sensor in its current iPhone before giving it up to give itself time to finalize the solution and offer it on the next evolution of its smartphones.