Fix compatibility with older mix versions

1 files changed, 1 insertions, 1 deletions

diff --git a/mix.exs b/mix.exs
index 4d1c451dc..461ae29c9 100644
--- a/mix.exs
+++ b/mix.exs
@@ -185,7 +185,7 @@ defmodule Ejabberd.MixProject do
   end
 
   defp elixir_required_version do
-    case {System.get_env("RELIVE", "false"),
+    case {Map.get(System.get_env(), "RELIVE", "false"),
           MapSet.member?(MapSet.new(System.argv()), "release")}
       do
       {"true", _} ->