diff --git a/mix.exs b/mix.exs
index 313b5cf..fec5b93 100644
--- a/mix.exs
+++ b/mix.exs
@@ -67,7 +67,7 @@ defmodule Surgex.Mixfile do
       {:ecto_sql, "~> 3.0"},
       {:jabbax, "~> 0.2 or ~> 1.0"},
       {:plug, "~> 1.7"},
-      {:timex, "~> 3.7"}
+      {:timex, "~> 3.7", optional: true}
     ]
     |> Enum.map(&merge_dep_flags(&1, optional: true))
   end