diff --git a/docs/rpc-spec.md b/docs/rpc-spec.md
index 21d842c48..69c37a463 100644
--- a/docs/rpc-spec.md
+++ b/docs/rpc-spec.md
@@ -603,6 +603,7 @@ except:
 * `rpc-version-semver`
 * `rpc-version`
 * `session-id`
+* `units`
 * `version`
 
 Response arguments: none