Migration Guide 10.x to 11.0 - jbogard/MediatR GitHub Wiki
This release contains breaking changes to interfaces using CancellationToken. C# design guidelines recommend CancellationToken parameters be placed last (CA1068). As such, these types were changed to conform to this rule:
IPipelineBehaviorIStreamPipelineBehaviorRequestExceptionActionProcessorBehaviorRequestExceptionProcessorBehaviorRequestPostProcessorBehaviorRequestPreProcessorBehavior
To fix these, move any implementations to have the CancellationToken parameter last.