diff --git a/mix.exs b/mix.exs
index 0f57c4dae..5484c43ef 100644
--- a/mix.exs
+++ b/mix.exs
@@ -213,7 +213,7 @@ defmodule Pleroma.Mixfile do
            true <- branch_name != "master" do
         branch_name =
           String.trim(branch_name)
-          |> String.replace(~r/\W+/, "-")
+          |> String.replace(~r/[^0-9a-z\-\.]+/i, "-")
 
         "-" <> branch_name
       end