diff --git a/gunicorn/config.py b/gunicorn/config.py
index 01f8a837..15b72bd1 100644
--- a/gunicorn/config.py
+++ b/gunicorn/config.py
@@ -1947,7 +1947,8 @@ class PostRequest(Setting):
         Called after a worker processes the request.
 
         The callable needs to accept two instance variables for the Worker and
-        the Request.
+        the Request. If a third parameter is defined it will be passed the
+        environment. If a fourth parameter is defined it will be passed the Response.
         """