diff --git a/dune-project b/dune-project
index bc89f54..0d57930 100644
--- a/dune-project
+++ b/dune-project
@@ -37,7 +37,8 @@
    (>= 0.8))
   printbox-md
   ptime
-  mtime
+  (mtime
+   (>= 1.4))
   re
   sexplib0
   (ppx_expect