diff --git a/features_cpp26.yaml b/features_cpp26.yaml
index a358780..3c0cfb6 100644
--- a/features_cpp26.yaml
+++ b/features_cpp26.yaml
@@ -1582,6 +1582,7 @@ features:
   - desc: "Future-proof `submdspan_mapping`"
     paper: P3663
     lib: true
+    support: [GCC 16]
 
   - desc: "Make `std::optional<T&>` trivially copyable"
     paper: P3836