The HTC M4 is expected to be a revision of the HTC One and we now know that it will be made out of a metal-alloy chassis and the supplier has already been selected. Catcher Technologym will be the exclusive provider for the chassis in order to avoid supply problems like what happened with the HTC One.
 
The HTC M4 should start shipping in June with wider availability in the third quarter of the year. HTC is has it’s sights set on shipping 700 000 devices in the second quarter.

Catcher forecasts a 10.5% to 15% sequential growth in revenue in Q2 2013. It is also expected to ship 2.3-2.4 million units of the HTC One in the second quarter.

Source Phone Arena