 
       config :ex_twilio, api_version: "2015-05-06"
   """
-  def api_version, do: @api_version
+  def api_version, do: Application.get_env(:ex_twilio, :api_version) || "2010-04-01"
 
   @doc """
   Return the combined base URL of the Twilio API, using the configuration 

defmodule ExTwilio.Config do
  @account_sid Application.get_env(:ex_twilio, :account_sid)
  @auth_token  Application.get_env(:ex_twilio, :auth_token)
  @api_domain  Application.get_env(:ex_twilio, :base_url) || "api.twilio.com"
  @api_version Application.get_env(:ex_twilio, :api_version) || "2010-04-01"

  @moduledoc """
  Provides easy access into ExTwilio's configuration for all the modules that
  need to know.
  """

  @doc """


      config :ex_twilio, api_domain: "other.twilio.com"
  """
  def api_domain,  do: Application.get_env(:ex_twilio, :api_domain) || "api.twilio.com"

  @doc """
  Returns the version of the API that ExTwilio is going to talk to. Set it in
