Releasing updates can be a pain sometimes. In the mobile space, it usually includes asking the user to download something again as well as refreshing their credentials in some way. Luke Wroblewski — who writes some tremendous material on mobile development — mentions in this post how you can announce your refresh with some panache and reward your users for continuing to use your product with some Easter eggs.
Don’t make the update a pain. It might mean some additional work will need to be done to include the artwork or new graphics. The UX team might need to rethink some of the work they thought was done.
Regardless, it’s important to the process and allows users to enjoy and share in the hard work you are doing!