diff --git a/rebar.config b/rebar.config
index 1f82fef6e..52bb8ead3 100644
--- a/rebar.config
+++ b/rebar.config
@@ -5,7 +5,7 @@
     , {gen_rpc, {git, "https://github.com/emqx/gen_rpc", {tag, "2.3.1"}}}
     , {ekka, {git, "https://github.com/emqx/ekka", {tag, "v0.5.5"}}}
     , {replayq, {git, "https://github.com/emqx/replayq", {tag, "v0.1.1"}}}
-    , {esockd, {git, "https://github.com/emqx/esockd", {tag, "v5.4.4"}}}
+    , {esockd, "5.5.0"}
     , {cuttlefish, {git, "https://github.com/emqx/cuttlefish", {tag, "v3.0.0"}}}
     ]}.
 
diff --git a/src/emqx_listeners.erl b/src/emqx_listeners.erl
index 104a9583a..65515a8d3 100644
--- a/src/emqx_listeners.erl
+++ b/src/emqx_listeners.erl
@@ -89,16 +89,18 @@ ranch_opts(Options) ->
     NumAcceptors = proplists:get_value(acceptors, Options, 4),
     MaxConnections = proplists:get_value(max_connections, Options, 1024),
     TcpOptions = proplists:get_value(tcp_options, Options, []),
-    RanchOpts = [{num_acceptors, NumAcceptors}, {max_connections, MaxConnections} | TcpOptions],
+    RanchOpts = #{num_acceptors => NumAcceptors,
+                  max_connections => MaxConnections,
+                  socket_opts => TcpOptions},
     case proplists:get_value(ssl_options, Options) of
         undefined  -> RanchOpts;
-        SslOptions -> RanchOpts ++ SslOptions
+        SslOptions -> RanchOpts#{socket_opts => TcpOptions ++ SslOptions}
     end.
 
-with_port(Port, Opts) when is_integer(Port) ->
-    [{port, Port}|Opts];
-with_port({Addr, Port}, Opts) ->
-    [{ip, Addr}, {port, Port}|Opts].
+with_port(Port, Opts = #{socket_opts := SocketOption}) when is_integer(Port) ->
+    Opts#{socket_opts => [{port, Port}| SocketOption]};
+with_port({Addr, Port}, Opts = #{socket_opts := SocketOption}) ->
+    Opts#{socket_opts => [{ip, Addr}, {port, Port}| SocketOption]}.
 
 %% @doc Restart all listeners
 -spec(restart() -> ok).
diff --git a/src/emqx_protocol.erl b/src/emqx_protocol.erl
index eb86a1841..4d266e8e3 100644
--- a/src/emqx_protocol.erl
+++ b/src/emqx_protocol.erl
@@ -1016,7 +1016,7 @@ do_check_banned(_EnableBan = true, Credentials) ->
         true  -> {error, ?RC_BANNED};
         false -> ok
     end;
-do_check_banned(_EnableBan, Credentials) -> ok.
+do_check_banned(_EnableBan, _Credentials) -> ok.
 
 do_acl_check(_EnableAcl = true, Action, Credentials, Topic) ->
     AllowTerm = ok,
diff --git a/src/emqx_zone.erl b/src/emqx_zone.erl
index 225d0ec4a..65deeea24 100644
--- a/src/emqx_zone.erl
+++ b/src/emqx_zone.erl
@@ -41,8 +41,12 @@
         , code_change/3
         ]).
 
+%% dummy state
+-record(state, {}).
+
 -define(TAB, ?MODULE).
 -define(SERVER, ?MODULE).
+-define(KEY(Zone, Key), {?MODULE, Zone, Key}).
 
 %%------------------------------------------------------------------------------
 %% APIs
@@ -62,7 +66,7 @@ get_env(Zone, Key) ->
 get_env(undefined, Key, Def) ->
     emqx_config:get_env(Key, Def);
 get_env(Zone, Key, Def) ->
-    try persistent_term:get({Zone, Key})
+    try persistent_term:get(?KEY(Zone, Key))
     catch error:badarg ->
         emqx_config:get_env(Key, Def)
     end.
@@ -84,7 +88,8 @@ stop() ->
 %%------------------------------------------------------------------------------
 
 init([]) ->
-    {ok, element(2, handle_info(reload, #{timer => undefined}))}.
+    _ = do_reload(),
+    {ok, #state{}}.
 
 handle_call(force_reload, _From, State) ->
     _ = do_reload(),
@@ -95,17 +100,13 @@ handle_call(Req, _From, State) ->
     {reply, ignored, State}.
 
 handle_cast({set_env, Zone, Key, Val}, State) ->
-    persistent_term:put({Zone, Key}, Val),
+    ok = persistent_term:put(?KEY(Zone, Key), Val),
     {noreply, State};
 
 handle_cast(Msg, State) ->
     ?LOG(error, "[Zone] Unexpected cast: ~p", [Msg]),
     {noreply, State}.
 
-handle_info(reload, State) ->
-    _ = do_reload(),
-    {noreply, ensure_reload_timer(State#{timer := undefined}), hibernate};
-
 handle_info(Info, State) ->
     ?LOG(error, "[Zone] Unexpected info: ~p", [Info]),
     {noreply, State}.
@@ -121,11 +122,6 @@ code_change(_OldVsn, State, _Extra) ->
 %%------------------------------------------------------------------------------
 
 do_reload() ->
-    [[persistent_term:put({Zone, Key}, Val)
-      || {Key, Val} <- Opts]
-     || {Zone, Opts} <- emqx_config:get_env(zones, [])].
+    [ persistent_term:put(?KEY(Zone, Key), Val)
+      || {Zone, Opts} <- emqx_config:get_env(zones, []), {Key, Val} <- Opts ].
 
-ensure_reload_timer(State = #{timer := undefined}) ->
-    State#{timer := erlang:send_after(timer:minutes(5), self(), reload)};
-ensure_reload_timer(State) ->
-    State.