It depends whether the consumers have any choice about whether to receive the update. If what you're versioning is a web app, they're getting the update no matt

It depends whether the consumers have any choice about whether to receive the update. If what you're versioning is a web app, they're getting the update no matter whether they think current and next are compatible or not. And if they aren't compatible in a way that's going to cause problems, you need to be communicating richer information to them than a change in a version number anyway.