I'd write a new review node. An update to the old review is likely never to be seen by the majority of potential readers. Even a notifying reply to it is not likely to get a lot of attention. Not touching the old node also retains context for the chatter hanging off it. And finally, there's a reason we keep docs for old versions of things around, and I think that applies here as well.

Just update the old review with a link to the new one at the top, saying that this review is for an old version of the module and not relevant for users of recent versions.

Makeshifts last the longest.