diff --git a/src/hb-open-type-private.hh b/src/hb-open-type-private.hh
index 437ecd5..558103a 100644
--- a/src/hb-open-type-private.hh
+++ b/src/hb-open-type-private.hh
@@ -592,7 +592,7 @@
     TRACE_SANITIZE (this);
     return TRACE_RETURN (likely (c->check_struct (this)));
   }
-  private:
+  protected:
   LONG major;
   ULONG minor;
   public: