They are very complicated pipelines to model. It is simpler if you simply treat other consumers of your services as customers who can't change their code at every whim. They've invested time and money in to your API, and are going to be pissed if you change it all the time.

Obviously this isn't the exact scenario you're in at the moment, but if you're big enough -- this is exactly what it'll be like.

Implement backwards compatible changes and implement tracking on the users of the old features you want to disable. When your tracking shows nobody is using the old features, delete them.

That is how we manage it.