This post applies to the Legacy database and the Cloud Database, but the Windows app does not have a New Year Setup procedure. See the Web App documentation for instructions.
No. All clubber and leader information and even the club session records remain in the database. The New Year Setup handles the grade and club promotions and creates a new set of club session records for the new year.
In the Legacy Database go to Admin > Database Utilities. Click the "New Year Setup" button.