diff --git a/spec/Section 6 -- Execution.md b/spec/Section 6 -- Execution.md
index d88c685f9..3716c71fe 100644
--- a/spec/Section 6 -- Execution.md	
+++ b/spec/Section 6 -- Execution.md	
@@ -20,6 +20,10 @@ Given this information, the result of {ExecuteRequest(schema, document,
 operationName, variableValues, initialValue)} produces the response, to be
 formatted according to the Response section below.
 
+A GraphQL service must ignore unrecognized information in a request. This allows
+a service to remain resilient to changes in future versions of this
+specification.
+
 Note: GraphQL requests do not require any specific serialization format or
 transport mechanism. Message serialization and transport mechanisms should be
 chosen by the implementing service.