As part of our FinTech mobile application deployment, we usually faced challenges coordinating the releases across backend APIs and mobile applications on iOS and Android platforms whenever we released significant new features. Typically, we will first deploy the backend APIs, as they are quick to deploy along with the database changes. Once the backend APIs are deployed, we publish the mobile applications for both iOS and Android platforms. The publishing process often takes time. The mobile application gets approved within a few hours and sometimes within a few days. If we raise the tickets with stores, the SLA (Service Level Agreement) for those tickets will span multiple days. The delays we saw were predominantly with Android in the last year or so.       

Once the back-end APIs are deployed, they initiate new workflows related to the new features. These could be new screens or a new set of data. However, the mobile application version available at that time for both platforms is not ready to accept these new screens as the newer app version has not been approved yet and would be in the store review process. This inconsistency can lead to a poor user experience which can manifest in various ways, such as the app not functioning correctly, the application crashing, or displaying an oops page or some internal errors.  This can be avoided by implementing feature flags on the backend APIs.