The ArcGIS Enterprise SDK in ArcGIS Enterprise 10.9.1 will be the last release to support .NET Framework 4.x-based Server Object Extensions (SOEs) and Server Object Interceptors (SOIs). Future versions of the ArcGIS Enterprise SDK will support .NET 6.
Customers and Esri business partners with .NET Framework-based SOEs and SOIs should begin planning for a move to .NET 6 at this time by identifying any .NET core library changes that will affect existing solutions as well as finding .NET 6 versions of any third-party libraries that are used.
The APIs exposed in the ArcGIS Enterprise SDK will include some minor breaking changes in addition to the move to .NET 6. Your use of ArcGIS Enterprise SDK APIs will also need to be reviewed when moving to ArcGIS Enterprise 11.0. Any impact is expected to be minimal.
ArcGIS Enterprise 11.0 will have a beta program in Q1 2022 that will include a first look at the .NET 6 support and updated APIs mentioned in this article. Affected customers and partners are encouraged to talk to their account and partner managers about how to participate in this beta program.