Please note that there is a major issue in firmware 66. As a consequence, commands sent from the plugin are not correctly handled.
A new firmware (v67) is coming to fix this issue.
Waiting for this fix, I recommend to avoid v66.
How long, i’ve just upgraded to v66 this weekend?
Things “seem” ok so far, just having a bit of trouble with the PLEG :-\
edit : has anyone got a copy of the V65 firmware so I can downgrade until this v67 comes out - can only get v66 from the RFXCOM web site /:
The version 66 zip file on the RFXCOM download page contains also version 64.
version 65 has not been released.
Oh ok, I’ve only had mine a few weeks and seem to remember it was shipped with v65, and I now remember seeing 64 with the download, cheers!! 
edit: Ive decided to “limp” on with v66 as I use the lightwave PIR’s and they didn’t really work correctly on v65… Any news on the next version anyone???
The update in version 65 is: Rubicson protocol enabling corrected
If you do not use Rubicson you can use version 64.
It is expected that version 67 will become available in a few weeks with only minor changes.
Firmwares v67 (type 1) and v167 (type 2) are now available on RFXCOM web site.
For people using v66, it is highly recommended to upgrade to v67.