I have forked a project and have changed lots of it. This fork isn't just a small feature change here and a buried bug fix there, its a pretty substantial change. Only most of the core code is shared.
I forked this project at v2.5.0. For a while I've started versioning my fork at v3.0 . However I'm not sure if this is the right way, mainly because when that project hits v3.0, things get confusing. But I don't want to start over at v1.0 or v0.1 because that implies infancy, instability, and non-refindness of a project. This isn't true, as most of the core code is very refined and stable.
I'm really lost on what to do, so I ask here: Whats the standard way to deal with this kind of situation? Do most forks start over again, bump up version numbers, or do something else that I'm not aware of.