When you publish an app replacing the one in the stream, all sheets created by users (Published and Community) will remain in the app and all Base Sheets will be replaced by this new version.
if you delete an app from the stream, all Published and Community are deleted too and there is no way to recover.
When applicable please mark the appropriate replies as CORRECT. This will help community members and Qlik Employees know which discussions have already been addressed and have a possible known solution. Please mark threads as HELPFUL if the provided solution is helpful to the problem, but does not necessarily solve the indicated problem. You can mark multiple threads as HELPFUL if you feel additional info is useful to others