This is an FYI so it gets picked up by Google in the future:
Despite not being listed as supported in the Qolsys supported device list, the 2GIG-DBELL1-345 doorbell works fine on the 345MHz version of the IQ Panel 4, as do 2GIG-STZ-1 Z-Wave thermostats. 100% of stuff hooked up to my old GC3 worked when I moved to an IQ Panel 4.