diff --git a/apps/state/mix.exs b/apps/state/mix.exs
index bd05ab7a..9286f24c 100644
--- a/apps/state/mix.exs
+++ b/apps/state/mix.exs
@@ -48,6 +48,8 @@ defmodule State.Mixfile do
   defp deps do
     [
       {:rstar, github: 'armon/erl-rstar', app: false},
+      # Needed for rstar
+      {:proper, "~> 1.4"},
       {:timex, "~> 3.7"},
       {:fetch, in_umbrella: true},
       {:events, in_umbrella: true},