Microsoft Sync Framework 2.1 still available and sample code

Introduction to Microsoft Sync Framework | Microsoft Learn

Sync Framework 2.1 is still available. 

Download Microsoft Sync Framework SDK 2.1 from Official Microsoft Download Center

Sample Code

In Sync - Creating Synchronization Providers With The Sync Framework | Microsoft Learn

Introducing Microsoft Sync Framework: Sync Services for File Systems | Microsoft Learn

Key features of the File system provider include:

• Incremental synchronization of changes between two file system locations specified via a local or UNC path.
• Synchronization of file contents, file and folder names, file timestamps, and attributes.
• Support for optional filtering of files based on filename/extensions, sub-directories, or file attributes
• Optional use of file hashes to detect changes to file contents if file timestamps are not reliable
• Reliable detection of conflicting changes to the same file and automatic resolution of conflicts with a no-data-loss policy
• Allow for limited user undo operation by optionally allowing file deletes and overwrites to be moved to the Recycle Bin
• Support for Preview mode which provides a preview of the incremental synchronization operation without committing changes to the file system.
• First-class support for the scenario where the user may start synchronization with equal or partially equal file hierarchies on more than one replica.
• Support for graceful cancellation of an ongoing synchronization operation such that the remaining changes can be synchronized later without having to re-synchronize changes that were already synchronized.