diff --git a/api/client-server/administrative_contact.yaml b/api/client-server/administrative_contact.yaml
index 504e149d..9a59cb6b 100644
--- a/api/client-server/administrative_contact.yaml
+++ b/api/client-server/administrative_contact.yaml
@@ -258,9 +258,7 @@ paths:
               id_access_token:
                 type: string
                 description: |-
-                  An access token previously registered with the identity server. Servers
-                  can treat this as optional to distinguish between r0.5-compatible clients
-                  and this specification version.
+                  An access token previously registered with the identity server.
               sid:
                 type: string
                 description: The session identifier given by the identity server.