diff --git a/bindings/ruby/database.c b/bindings/ruby/database.c
index 44ee6817..fae5af28 100644
--- a/bindings/ruby/database.c
+++ b/bindings/ruby/database.c
@@ -156,7 +156,7 @@ notmuch_rb_upgrade_notify(void *closure, double progress)
 }
 
 /*
- * call-seq: DB.upgrade [{|progress| block }] => nil
+ * call-seq: DB.upgrade! [{|progress| block }] => nil
  *
  * Upgrade the database.
  *