diff --git a/config/runtime.exs b/config/runtime.exs
index 0f74dcc..3a8e363 100644
--- a/config/runtime.exs
+++ b/config/runtime.exs
@@ -83,7 +83,7 @@ if config_env() == :prod do
   # Check `Plug.SSL` for all available options in `force_ssl`.
 
   config :tusker_push, :apns,
-    key_pem: System.fetch_env!("APNS_KEY_PEM"),
+    key_pem: File.read!(System.fetch_env!("APNS_KEY_PEM_PATH")),
     key_id: System.fetch_env!("APNS_KEY_ID"),
     team_id: System.fetch_env!("APNS_TEAM_ID"),
     bundle_id: System.fetch_env!("APNS_BUNDLE_ID")