Originally Posted by Commodore
Nope. It's one of those unspoken things in Trek (such as the Enterprise-E being a Sovereign-class starship). In fact, the only official thing we know about warp scales period is that each subsequent warp factor is presumably faster than the previous one and that "maximum warp" varies from ship to ship. Otherwise, both the TOS and TNG warp scales are totally non-canon and have been pretty much contradicted in every episode involving speeds and travel times to boot.
The only reason why it is presumed there was a recalibration in the warp scale was because of behind-the-scenes information and because the Enterprise-D would be otherwise slower than the original Enterprise.
Thanks for confirming - I didn't think it had ever been gone over 'officially'.