It's not v8 at least, I use it on 7 just fine (though I do use the cloud offering). I don't see why it would be tied to that though considering it's just an API integration that saves the card into your 1password for the site you're on and then fills in the credentials. That _should_ theoretically work with a local vault as well on v7.

That same logic holds for the fastmail vanity email aliases, too, in that it's just an API integration; does your v7+cloud have that integration, too?

It does! I was actually considering switching to BitWarden right when the Fastmail integration came out and that's what kept me with 1Password.