While the interface's signature uses the deprecated "Library" type, and upstream documents it as "needed for backward compatibility"; https://github.com/open-telemetry/opentelemetry-go/blob/0f7f1d0bad21aba18feaadc0171c53705fbda419/sdk/trace/span.go#L62-L65 The Library type is now an alias for Scope, so using the non-deprecated type still satisfies the interface; https://github.com/open-telemetry/opentelemetry-go/blob/0f7f1d0bad21aba18feaadc0171c53705fbda419/sdk/instrumentation/library.go#L6-L9 Signed-off-by: Sebastiaan van Stijn <github@gone.nl>