diff --git a/etc/emq.conf b/etc/emq.conf
index 677eca905..898a94576 100644
--- a/etc/emq.conf
+++ b/etc/emq.conf
@@ -1,5 +1,5 @@
 ##====================================================================
-## EMQ Configuration R2.3.3
+## EMQ Configuration R2
 ##====================================================================
 
 ##--------------------------------------------------------------------
@@ -9,7 +9,17 @@
 ## Cluster name
 cluster.name = emqcl
 
-## Cluster discovery strategy: manual | static | mcast | dns | etcd | k8s
+## Cluster auto-discovery strategy.
+##
+## Enum Values:
+## - manual: Manual join command
+## - static: Static node list
+## - mcast:  IP Multicast
+## - dns:    DNS A Record
+## - etcd:   etcd
+## - k8s:    Kubernates
+##
+## Default: manual
 cluster.discovery = manual
 
 ## Cluster Autoheal: on | off
@@ -557,7 +567,9 @@ listener.wss.external.access.1 = allow all
 ## listener.wss.external.proxy_protocol = on
 ## listener.wss.external.proxy_protocol_timeout = 3s
 
-## SSL Options
+## SSL Option
+### SSL Options. See http://erlang.org/doc/man/ssl.html
+
 listener.wss.external.handshake_timeout = 15s
 
 listener.wss.external.keyfile = {{ platform_etc_dir }}/certs/key.pem