 
   defp parse_args(argv) do
     switches = [silent: :boolean, quiet: :boolean, verbose: :boolean,
-                dev: :boolean, erl: :string, no_tar: :boolean]
+                dev: :boolean, erl: :string, no_tar: :boolean,
+                upgrade: :boolean, upfrom: :string]
     {overrides, _} = OptionParser.parse!(argv, switches)
     verbosity = :normal
     verbosity = cond do


      # Build a release using defaults
      mix release

      # Pass args to erlexec when running the release
      mix release --erl="-env TZ UTC"

               nil -> config
               o   -> %{config | :erl_opts => o}
             end
    config = %{config |
               :is_upgrade => Keyword.fetch!(opts, :is_upgrade),
               :upgrade_from => Keyword.fetch!(opts, :upgrade_from)}
    no_tar? = Keyword.get(opts, :no_tar)

    # build release
