You mentioned this micra is compatible with ELK panel/wireless receiver but I don't believe Elk has an updated firmware for the main security panel and the wireless receiver so it would work with Micra. I believe Elk is working on this firmware or at least that is what they indicated in some of the email traffic.
Tuantu - why do you think Elk needs updated firmware to support these? The sensors apparently use the same frequency that the GE sensors use and the folks at Ion-digital said, and I quote from the direct question I asked them:
Our Micra-G and Plunger-G are compatible with all current GE receivers or where 319.5 MHz sensors are used. They should work just fine with the M1XFR2G zone expander.
Is there something I'm missing? I'm about to place an order and don't want to end up with useless stuff if there's something key I'm missing about the Elk.