Version 1.8.0 is very recent and with the Switch 2 release, a lot of changes are being discussed right now, so the new rules might take a bit long before coming. However it is certain that the newest version will still be allowed in the next rules, so even if there's a lot of uncertainities at the moment, you can still speedrun in your version. By the way if you're wondering what the 1.8.0 great plateau route is, it's the one from before BLSS was discovered.
Version 1.8 is the update for the Switch 2 and like @Ram_Sr said its very recent and everyone is still figuring it all out. Since you updated the game, you will have to do the old route (with some adjustments here and there) with the new castle route for Any%, at least from what I've gathered.
