Update Old .NET Desktop Application

ONLY FREELANCERS NO COMAPNIES Hi, I have an old .NET desktop application (around 8–9 years old) which runs as a small EXE and currently uses SQL Server Compact Edition database. We need to make some modifications: 1) Migrate the existing SQL Server Compact Edition database to a modern database system. 2) Offline-First Architecture with Auto Sync: The application should continue working offline. When internet is available, backup/offline entries should automatically sync to the main database/server. 3) The software currently has a 1-year expiry key/license system already implemented we need to change few thing here only small changes. 4) some small changes to our exe application. Please let me know: Your experience with old .NET WinForms/WPF applications