diff --git a/apps/emqx/src/emqx_channel.erl b/apps/emqx/src/emqx_channel.erl
index 07aad9b24..6c9c8f8a8 100644
--- a/apps/emqx/src/emqx_channel.erl
+++ b/apps/emqx/src/emqx_channel.erl
@@ -37,7 +37,6 @@
     get_mqtt_conf/2,
     get_mqtt_conf/3,
     set_conn_state/2,
-    set_conninfo_proto_ver/2,
     stats/1,
     caps/1
 ]).
@@ -220,9 +219,6 @@ info(impl, #channel{session = Session}) ->
 set_conn_state(ConnState, Channel) ->
     Channel#channel{conn_state = ConnState}.
 
-set_conninfo_proto_ver({none, #{version := ProtoVer}}, Channel = #channel{conninfo = ConnInfo}) ->
-    Channel#channel{conninfo = ConnInfo#{proto_ver => ProtoVer}}.
-
 -spec stats(channel()) -> emqx_types:stats().
 stats(#channel{session = undefined}) ->
     emqx_pd:get_counters(?CHANNEL_METRICS);