Comment 4 for bug 1393952

> That doesn't answer the question of versions though, which may change
> when capabilities do not. There may be some other semantic change
> which is implicit in a version bump.

Explicitly signalling semantic changes is what that view is meant for.
It was designed so that people would not use version numbers and not
come to depend on implicit behaviour changes.

Capabilities can be turned on and off. Version numbers can only move
forwards. There's no way to signal via a version number that something
that once was available is no longer available. Instead, all clients
must be updated.

> We can add the version/revision info in the capabilities structre
> easily enough.

Please see if you can avoid doing that.