HR-150's are. Depending on what the MLX-3 is doing for control, I would rather sell the customer an HR150 than a POS MLX-3. You can also install an HR-310 and use the HR-150 programming, you just need to omit hard button 9 on the 310.

Alternatively you could put in an RMC3 with the TSR-310 and EISC from SB project to RMC3. Since the 310 doesn't need a gateway and connects to the WIFI this may be the start of a systems upgrade.