I currently have a v4 invision community. Let's call this community A for example.
If I set up a new v4 (community B) (as v5 isn't released yet) invision community and use my existing v4 community A as the master oAuth login server, and then the new invision community B members can login with their pre-existing community A login. My question is, if I upgrade community B to v5 at release, but keep my community A as v4, will that still work fine with the logins on the new community?
I do not wish to upgrade my old community as too many plugins and applications but would like an additional forum where they can login with their existing login.
I presume upgrade from v4 to v5 will be absolutely fine.