You have no idea just how much this excerpt of Fowler’s write-up of Published Interfaces
smells of my workplace. I have to double-check our consulting roster for his name.

<Fowler on deprecation in unpublished interfaces>

Don�t treat interfaces as published unless they are. If you need
to change an interface and can find and change all users, then don�t bother
going through all the forwarding and deprecation gambits.
Just make the change and update the users.