You can’t guarantee that users will ever update to the latest version of an app, so you can expect that a few users will remain on every historic version of your app.
APIs that support your app are likely to evolve. Maintaining and running old versions of an API is expensive. You need to pay for the platform it runs on, you need to pay for the maintenance needed to keep it secure and working. Sooner or later, you should decommission it.
However, when you turn an API off, any historic versions of your app still using it will stop working. This could also be expensive. You could lose users who are contributing to your revenue stream. Or, you might get poor ratings in the App Stores, making it harder and more expensive for you to acquire new users.
To decide if or when to decommission an API, you need to balance the cost of keeping the API alive with the cost of losing users. This article covers the things you need to consider when assessing when and how you should decommission your API…