We have an API server, which serves both of our web app and mobile app (both Android, IOS).
We have to shut down database servers sometimes for up-gradation or maintenance, so the site shows Maintenance in Progress kind of page.
It works for the web app, but what to do about the mobile app? We can't show any kind of maintenance board on the app to stop the app calling APIs, so all requests on mobile app ends up with no response from API server and fail. How this scenario is handled? What is the common practice?