How to painlessly update an API?

Question

API

Good afternoon
There is an API, it is updated from time to time. It is necessary to somehow transfer clients painlessly to use the new API
. Obviously, the problem is far from new, there are a lot of pitfalls, for example, the slowness of clients who do not want to switch at all and want to use the old API, and a bunch of others.
I would like to hear the opinion of experts who have already stepped on a rake as an answer to the question: "how to painlessly make changes to an existing (and widely used 24/7) API?"
Or at least links to read (well, habr, for example, I searched - I didn’t find it ((( )
Thank you

Answer 1

Documentation + Versioning + Roadmap
See how it's implemented:
Vkontakte:
https://vk.com/dev/versions
https://vk.com/dev/roadmap
Facebook:
https://developers.facebook.com/docs/ apps/versions/
https://developers.facebook.com/docs/graph-api/cha...