I don't know the extent of the changes, but noticed a different trailer wiring connection on the 2013 RT Limited and RT-622 trailer displayed at the Atlanta motorcycle show. When looking in the '2013 CAN-AM ROADSTER GENUINE PARTS, ACCESSORIES & RIDING GEAR' catalog, on page 70, there is this part:

RT-622 Tongue harness
Converts 2011 and 2012 RT-622
Trailers for compatibility with 2013
hitch and module (RT and ST), and
2013 4-pin adaptor.
RT-622 2011 to 2013 710003227
$39.99

This apparently is used with the '4 Pin Trailer Adaptor Harness' on the same page. There are 2 of these listed, one for RT-622 2013 and one for RT-622 2012 and prior.

The display model had a completely different hookup, but ALSO had what appeared to be the familiar 9 pin hookup. The BRP rep said that was a non production RT and couldn't say which the production unit would use. I don't see an adapter for the 2013 RT or ST to pull the 2010 RT-622 trailer.

Bottom line, in four production years, they now have three different configurations.

Crazy...