diff --git a/src/librustdoc/json/mod.rs b/src/librustdoc/json/mod.rs
index f8bd971081395..0d84bf250c9e3 100644
--- a/src/librustdoc/json/mod.rs
+++ b/src/librustdoc/json/mod.rs
@@ -234,7 +234,7 @@ impl<'tcx> FormatRenderer<'tcx> for JsonRenderer<'tcx> {
                     )
                 })
                 .collect(),
-            format_version: 5,
+            format_version: 6,
         };
         let mut p = self.out_path.clone();
         p.push(output.index.get(&output.root).unwrap().name.clone().unwrap());