I just got in front of CCP and it was an option when under "configure home" area, adding a new remote (MXW920) and select the "copy from"..the drop down dialog shows the MX900 (since it is already in the configuration).
Cool. I'll need to check to make sure all the base station assignments are accurate (I have 3 MSC400 in this system) but so far all looks good!
Impetus to this: The customer had a MX900 operating his outside pool system for several years. Teenage son left it out and it got severally rained on and quit working. I pitched the 920 and he decided it would be prudent.
Chasing Ernie's post count, one useless post at a time.