I think all we need to do is change the version to Infinispan 8.latest.stable and forget about Infinispan 7 compatibility needs. Check documentation update needs.

Radim wanted to do it as he's also planning to take advantage of this move, but I guess we could start with switching the versions only?

I'd wait for this as long as you are not needing to release a 5.1.x of ORM, so that we might be using an Infinispan 8.1.x release rather than 8.0.x release (there is no stable release of Infinispan 8.1.0 yet)