No change. There never was a change. Motorcycles with just the rider are OK - and signs indicate thus - on roads administered by the city of Toronto. Motorcycles with just the rider are not allowed in HOV lanes anywhere else and the signs don't indicate so, either.
The only thing that changes is that if you are carrying a passenger you can use the 2-person HOV. The 3-person HOV ruled out the use of ALL vehicles that can only carry two people. Motorcycle, Corvette, Miata, smart, standard-cab trucks with only two seats, etc. But it was only incidental, as a side effect of requiring 3 people. It was never explicit ... you just couldn't legally meet the 3-person requirement with those vehicles.