What are the key challenges in maintaining a mobile app after launch?

I’m interested in understanding the common challenges businesses face after launching a mobile app. Issues such as bug fixes, performance problems, security updates, OS compatibility, and feature improvements can require ongoing technical support.

For those who have managed mobile apps, what maintenance issues have you found most important to address, and what should businesses consider when looking for a reliable mobile app maintenance company?

I came across JPLoft while researching mobile app maintenance services. Has anyone had experience with their services or similar providers?