You update all the callers of B that you can see from your codebase. If `B` is a library then you publish an out-of-band notice that `B` is deprecated and they

You update all the callers of B that you can see from your codebase. If `B` is a library then you publish an out-of-band notice that `B` is deprecated and they should switch to `B'`. It's the most extreme form of static linking you can think of (which is really nice for stability, not nice for speed-to-deploy-a-change).