6.5 and 6.7 are officially tested and supported although I don't recall seeing anything specific to 7.0 and the GA was released in April, but I don't see any reason it wouldn't work... probably just isn't tested and verified yet. The chances any Mitel VM would work are very high. That said, most places I know are on 6.7 and won't consider upgrading to 7.0 until it has been out a minimum of 6-12 months to verify stability.
