I’m all for updating and upgrading mobile apps. I think if you’re not constantly looking at ways to improve the user experience, it’s just too easy to fall behind.
That said, a redesign should be done for the right reasons.
If it’s an existing app that’s already popular with users, any changes made to the design or content should be done in very small, incremental, strategic chunks through A/B testing.
https://www.smashingmagazine.com/2020/07/redesigning-mobile-app/