Add decision about v2 API

CONTRIBUTING.md

@@ -470,8 +470,33 @@ doumentation are allowed to be extended with additional methods.
 
 > Warning: methods may be added to this interface in minor releases.
 
+These interfaces are defined by the OpenTelemetry specification and will be
+updated as the specification evolves.
+
 Otherwise, stable interfaces MUST NOT be modified.
 
+#### How to Change Specification Interfaces
+
+When an API change must be made, we will update the SDK with the new method one
+release before the API change. This will allow the SDK one version before the
+API change to work seemlessly with the new API.
+
+If an incompatible version of the SDK is used with the new API the application
+will fail to compile.
+
+#### How Not to Change Specification Interfaces
+
+We have explored using a v2 of the API to change interfaces and found that there
+was no way to introduce a v2 and have it seamlessly work with the v1 of the API.
+Problems happened libraries that upgraded to v2 when an application did not
+would not produce any telemetry.
+
+More detail of the approaches considered and their limitations can be found in
+the [Use a V2 API to evolve interfaces](https://github.com/open-telemetry/opentelemetry-go/issues/3920)
+issue.
+
+#### How to Change Other Interfaces
+
 If new functionality is needed for an interface that cannot be changed it MUST
 be added by including an additional interface. That added interface can be a
 simple interface for the specific functionality that you want to add or it can