If you are talking about the sensor/camera itself I'm sorry but you are stuck with whatever HTC offered at MWC.
I had to explain this in the S6 thread. The phones you saw at MWC are the phones you will receive in the store. Companies have to start manufacturing phones weeks in advance to meet supply/demand. For example, if Samsung had 20 million orders from carriers do you think they started producing those phones this weekend? Not at all, the manufacturing process doesn't work that way.
There are HTC M9's sitting I'm warehouses as I type. Any hardware problems won't be resolved because those phones have already been manufactured.