The FIT C# SDK is now available from NuGet
https://www.nuget.org/packages/Garmin.FIT.Sdk 

The source code for the FIT C# SDK is also available in GitHub
https://github.com/garmin/fit-csharp-sdk 

The FIT C# SDK will continue to be available from the Garmin Developer site
https://developer.garmin.com/fit/download 

The FIT C#, Java, JavaScript, Objective-C, and Python SDKs are now all available through their respective package managers and GitHub. 

FIT C# SDK
https://www.nuget.org/packages/Garmin.FIT.Sdk 
https://github.com/garmin/fit-csharp-sdk 

FIT Java SDK
https://central.sonatype.com/artifact/com.garmin/fit 
https://github.com/garmin/fit-java-sdk 

FIT JavaScript SDK
https://www.npmjs.com/package/@garmin-fit/sdk 
https://github.com/garmin/fit-javascript-sdk 

FIT Objective-C SDK
https://github.com/garmin/fit-objective-c-sdk 

FIT Python SDK
https://pypi.org/project/garmin-fit-sdk 
https://github.com/garmin/fit-python-sdk 

All FIT SDKs will continue to be available from the Garmin Developer site
https://developer.garmin.com/fit/download 

Anonymous