Documents undocumented configuration keys

celery/app/defaults.py

@@ -50,13 +50,13 @@ NAMESPACES = {
         "USER": Option(None, type="string"),
         "PASSWORD": Option(None, type="string"),
         "VHOST": Option(None, type="string"),
-        "BACKEND": Option(None, type="string"),
         "CONNECTION_TIMEOUT": Option(4, type="int"),
         "CONNECTION_RETRY": Option(True, type="bool"),
         "CONNECTION_MAX_RETRIES": Option(100, type="int"),
         "POOL_LIMIT": Option(None, type="int"),
         "INSIST": Option(False, type="bool"),
         "USE_SSL": Option(False, type="bool"),
+        "TRANSPORT": Option(None, type="string"),
         "TRANSPORT_OPTIONS": Option({}, type="dict"),
     },
     "CELERY": {

docs/configuration.rst

@@ -987,6 +987,14 @@ EMAIL_PORT
 
 The port the mail server is listening on.  Default is `25`.
 
+
+.. setting:: EMAIL_USE_SSL
+
+EMAIL_USE_SSL
+~~~~~~~~~~~~~
+
+Use SSL when connecting to the SMTP server.  Disabled by default.
+
 .. setting:: EMAIL_TIMEOUT
 
 EMAIL_TIMEOUT