diff --git a/src/emqx_access_control.erl b/src/emqx_access_control.erl
index 06e8f5ed8..ff5ad9d09 100644
--- a/src/emqx_access_control.erl
+++ b/src/emqx_access_control.erl
@@ -28,7 +28,7 @@
 %% APIs
 %%--------------------------------------------------------------------
 
--spec(authenticate(emqx_types:client())
+-spec(authenticate(emqx_types:client_info())
       -> {ok, #{auth_result := emqx_types:auth_result(),
                 anonymous := boolean}} | {error, term()}).
 authenticate(Client) ->
diff --git a/src/emqx_access_rule.erl b/src/emqx_access_rule.erl
index e48caa5c0..690b45998 100644
--- a/src/emqx_access_rule.erl
+++ b/src/emqx_access_rule.erl
@@ -86,23 +86,23 @@ bin(B) when is_binary(B) ->
     B.
 
 %% @doc Match access rule
--spec(match(emqx_types:client(), emqx_types:topic(), rule())
+-spec(match(emqx_types:client_info(), emqx_types:topic(), rule())
       -> {matched, allow} | {matched, deny} | nomatch).
-match(_Client, _Topic, {AllowDeny, all}) when ?ALLOW_DENY(AllowDeny) ->
+match(_ClientInfo, _Topic, {AllowDeny, all}) when ?ALLOW_DENY(AllowDeny) ->
     {matched, AllowDeny};
-match(Client, Topic, {AllowDeny, Who, _PubSub, TopicFilters})
+match(ClientInfo, Topic, {AllowDeny, Who, _PubSub, TopicFilters})
     when ?ALLOW_DENY(AllowDeny) ->
-    case match_who(Client, Who)
-         andalso match_topics(Client, Topic, TopicFilters) of
+    case match_who(ClientInfo, Who)
+         andalso match_topics(ClientInfo, Topic, TopicFilters) of
         true  -> {matched, AllowDeny};
         false -> nomatch
     end.
 
-match_who(_Client, all) ->
+match_who(_ClientInfo, all) ->
     true;
-match_who(_Client, {user, all}) ->
+match_who(_ClientInfo, {user, all}) ->
     true;
-match_who(_Client, {client, all}) ->
+match_who(_ClientInfo, {client, all}) ->
     true;
 match_who(#{client_id := ClientId}, {client, ClientId}) ->
     true;
@@ -112,44 +112,44 @@ match_who(#{peerhost := undefined}, {ipaddr, _Tup}) ->
     false;
 match_who(#{peerhost := IP}, {ipaddr, CIDR}) ->
     esockd_cidr:match(IP, CIDR);
-match_who(Client, {'and', Conds}) when is_list(Conds) ->
+match_who(ClientInfo, {'and', Conds}) when is_list(Conds) ->
     lists:foldl(fun(Who, Allow) ->
-                  match_who(Client, Who) andalso Allow
+                  match_who(ClientInfo, Who) andalso Allow
                 end, true, Conds);
-match_who(Client, {'or', Conds}) when is_list(Conds) ->
+match_who(ClientInfo, {'or', Conds}) when is_list(Conds) ->
     lists:foldl(fun(Who, Allow) ->
-                  match_who(Client, Who) orelse Allow
+                  match_who(ClientInfo, Who) orelse Allow
                 end, false, Conds);
-match_who(_Client, _Who) ->
+match_who(_ClientInfo, _Who) ->
     false.
 
-match_topics(_Client, _Topic, []) ->
+match_topics(_ClientInfo, _Topic, []) ->
     false;
-match_topics(Client, Topic, [{pattern, PatternFilter}|Filters]) ->
-    TopicFilter = feed_var(Client, PatternFilter),
+match_topics(ClientInfo, Topic, [{pattern, PatternFilter}|Filters]) ->
+    TopicFilter = feed_var(ClientInfo, PatternFilter),
     match_topic(emqx_topic:words(Topic), TopicFilter)
-        orelse match_topics(Client, Topic, Filters);
-match_topics(Client, Topic, [TopicFilter|Filters]) ->
+        orelse match_topics(ClientInfo, Topic, Filters);
+match_topics(ClientInfo, Topic, [TopicFilter|Filters]) ->
    match_topic(emqx_topic:words(Topic), TopicFilter)
-       orelse match_topics(Client, Topic, Filters).
+       orelse match_topics(ClientInfo, Topic, Filters).
 
 match_topic(Topic, {eq, TopicFilter}) ->
     Topic == TopicFilter;
 match_topic(Topic, TopicFilter) ->
     emqx_topic:match(Topic, TopicFilter).
 
-feed_var(Client, Pattern) ->
-    feed_var(Client, Pattern, []).
-feed_var(_Client, [], Acc) ->
+feed_var(ClientInfo, Pattern) ->
+    feed_var(ClientInfo, Pattern, []).
+feed_var(_ClientInfo, [], Acc) ->
     lists:reverse(Acc);
-feed_var(Client = #{client_id := undefined}, [<<"%c">>|Words], Acc) ->
-    feed_var(Client, Words, [<<"%c">>|Acc]);
-feed_var(Client = #{client_id := ClientId}, [<<"%c">>|Words], Acc) ->
-    feed_var(Client, Words, [ClientId |Acc]);
-feed_var(Client = #{username := undefined}, [<<"%u">>|Words], Acc) ->
-    feed_var(Client, Words, [<<"%u">>|Acc]);
-feed_var(Client = #{username := Username}, [<<"%u">>|Words], Acc) ->
-    feed_var(Client, Words, [Username|Acc]);
-feed_var(Client, [W|Words], Acc) ->
-    feed_var(Client, Words, [W|Acc]).
+feed_var(ClientInfo = #{client_id := undefined}, [<<"%c">>|Words], Acc) ->
+    feed_var(ClientInfo, Words, [<<"%c">>|Acc]);
+feed_var(ClientInfo = #{client_id := ClientId}, [<<"%c">>|Words], Acc) ->
+    feed_var(ClientInfo, Words, [ClientId |Acc]);
+feed_var(ClientInfo = #{username := undefined}, [<<"%u">>|Words], Acc) ->
+    feed_var(ClientInfo, Words, [<<"%u">>|Acc]);
+feed_var(ClientInfo = #{username := Username}, [<<"%u">>|Words], Acc) ->
+    feed_var(ClientInfo, Words, [Username|Acc]);
+feed_var(ClientInfo, [W|Words], Acc) ->
+    feed_var(ClientInfo, Words, [W|Acc]).
 
diff --git a/src/emqx_banned.erl b/src/emqx_banned.erl
index 7e3e959e3..d41f32ee0 100644
--- a/src/emqx_banned.erl
+++ b/src/emqx_banned.erl
@@ -73,7 +73,7 @@ start_link() ->
 -spec(stop() -> ok).
 stop() -> gen_server:stop(?MODULE).
 
--spec(check(emqx_types:client()) -> boolean()).
+-spec(check(emqx_types:client_info()) -> boolean()).
 check(#{client_id := ClientId,
         username  := Username,
         peerhost  := IPAddr}) ->
diff --git a/src/emqx_channel.erl b/src/emqx_channel.erl
index edd08baa6..5d76f8414 100644
--- a/src/emqx_channel.erl
+++ b/src/emqx_channel.erl
@@ -60,7 +60,7 @@
           %% MQTT ConnInfo
           conninfo :: emqx_types:conninfo(),
           %% MQTT ClientInfo
-          client :: emqx_types:client(),
+          client_info :: emqx_types:client_info(),
           %% MQTT Session
           session :: emqx_session:session(),
           %% Keepalive
@@ -102,7 +102,7 @@
           will_timer   => will_message
          }).
 
--define(ATTR_KEYS, [conninfo, client, session, connected, connected_at, disconnected_at]).
+-define(ATTR_KEYS, [conninfo, client_info, session, connected, connected_at, disconnected_at]).
 -define(INFO_KEYS, ?ATTR_KEYS ++ [keepalive, topic_aliases, alias_maximum, gc_state, disconnected_at]).
 
 %%--------------------------------------------------------------------
@@ -119,7 +119,7 @@ info(Keys, Channel) when is_list(Keys) ->
     [{Key, info(Key, Channel)} || Key <- Keys];
 info(conninfo, #channel{conninfo = ConnInfo}) ->
     ConnInfo;
-info(client, #channel{client = ClientInfo}) ->
+info(client_info, #channel{client_info = ClientInfo}) ->
     ClientInfo;
 info(session, #channel{session = Session}) ->
     maybe_apply(fun emqx_session:info/1, Session);
@@ -158,7 +158,7 @@ stats(#channel{session = Session}) ->
     emqx_session:stats(Session).
 
 -spec(caps(channel()) -> emqx_types:caps()).
-caps(#channel{client = #{zone := Zone}}) ->
+caps(#channel{client_info = #{zone := Zone}}) ->
     emqx_mqtt_caps:get_caps(Zone).
 
 %% For tests
@@ -196,15 +196,15 @@ init(ConnInfo = #{peername := {PeerHost, _Port}, protocol := Protocol}, Options)
                      true  -> undefined;
                      false -> disabled
                  end,
-    #channel{conninfo   = ConnInfo,
-             client     = ClientInfo,
-             gc_state   = init_gc_state(Zone),
-             oom_policy = init_oom_policy(Zone),
-             timers     = #{stats_timer => StatsTimer},
-             connected  = undefined,
-             takeover   = false,
-             resuming   = false,
-             pendings   = []
+    #channel{conninfo    = ConnInfo,
+             client_info = ClientInfo,
+             gc_state    = init_gc_state(Zone),
+             oom_policy  = init_oom_policy(Zone),
+             timers      = #{stats_timer => StatsTimer},
+             connected   = undefined,
+             takeover    = false,
+             resuming    = false,
+             pendings    = []
             }.
 
 peer_cert_as_username(Options) ->
@@ -252,7 +252,7 @@ handle_in(Packet = ?PUBLISH_PACKET(_QoS), Channel) ->
     end;
 
 handle_in(?PUBACK_PACKET(PacketId, _ReasonCode),
-          Channel = #channel{client = ClientInfo, session = Session}) ->
+          Channel = #channel{client_info = ClientInfo, session = Session}) ->
     case emqx_session:puback(PacketId, Session) of
         {ok, Msg, Publishes, NSession} ->
             ok = emqx_hooks:run('message.acked', [ClientInfo, Msg]),
@@ -271,7 +271,7 @@ handle_in(?PUBACK_PACKET(PacketId, _ReasonCode),
     end;
 
 handle_in(?PUBREC_PACKET(PacketId, _ReasonCode),
-          Channel = #channel{client = ClientInfo, session = Session}) ->
+          Channel = #channel{client_info = ClientInfo, session = Session}) ->
     case emqx_session:pubrec(PacketId, Session) of
         {ok, Msg, NSession} ->
             ok = emqx_hooks:run('message.acked', [ClientInfo, Msg]),
@@ -310,7 +310,7 @@ handle_in(?PUBCOMP_PACKET(PacketId, _ReasonCode), Channel = #channel{session = S
     end;
 
 handle_in(Packet = ?SUBSCRIBE_PACKET(PacketId, Properties, TopicFilters),
-          Channel = #channel{client = ClientInfo}) ->
+          Channel = #channel{client_info = ClientInfo}) ->
     case emqx_packet:check(Packet) of
         ok -> TopicFilters1 = emqx_hooks:run_fold('client.subscribe',
                                                   [ClientInfo, Properties],
@@ -323,7 +323,7 @@ handle_in(Packet = ?SUBSCRIBE_PACKET(PacketId, Properties, TopicFilters),
     end;
 
 handle_in(Packet = ?UNSUBSCRIBE_PACKET(PacketId, Properties, TopicFilters),
-          Channel = #channel{client = ClientInfo}) ->
+          Channel = #channel{client_info = ClientInfo}) ->
     case emqx_packet:check(Packet) of
         ok -> TopicFilters1 = emqx_hooks:run_fold('client.unsubscribe',
                                                   [ClientInfo, Properties],
@@ -369,7 +369,7 @@ handle_in(Packet, Channel) ->
 %%--------------------------------------------------------------------
 
 process_connect(ConnPkt = #mqtt_packet_connect{clean_start = CleanStart},
-                Channel = #channel{conninfo = ConnInfo, client = ClientInfo}) ->
+                Channel = #channel{conninfo = ConnInfo, client_info = ClientInfo}) ->
     case emqx_cm:open_session(CleanStart, ClientInfo, ConnInfo) of
         {ok, #{session := Session, present := false}} ->
             NChannel = Channel#channel{session = Session},
@@ -440,7 +440,7 @@ process_publish(PacketId, Msg = #message{qos = ?QOS_2},
     end.
 
 publish_to_msg(Packet, #channel{conninfo = #{proto_ver := ProtoVer},
-                                client   = ClientInfo = #{mountpoint := MountPoint}}) ->
+                                client_info = ClientInfo = #{mountpoint := MountPoint}}) ->
     Msg = emqx_packet:to_message(ClientInfo, Packet),
     Msg1 = emqx_message:set_flag(dup, false, Msg),
     Msg2 = emqx_message:set_header(proto_ver, ProtoVer, Msg1),
@@ -461,7 +461,7 @@ process_subscribe([{TopicFilter, SubOpts}|More], Acc, Channel) ->
     process_subscribe(More, [RC|Acc], NChannel).
 
 do_subscribe(TopicFilter, SubOpts = #{qos := QoS}, Channel =
-             #channel{client  = ClientInfo = #{mountpoint := MountPoint},
+             #channel{client_info = ClientInfo = #{mountpoint := MountPoint},
                       session = Session}) ->
     case check_subscribe(TopicFilter, SubOpts, Channel) of
         ok ->
@@ -491,7 +491,7 @@ process_unsubscribe([{TopicFilter, SubOpts}|More], Acc, Channel) ->
     process_unsubscribe(More, [RC|Acc], NChannel).
 
 do_unsubscribe(TopicFilter, _SubOpts, Channel =
-               #channel{client  = ClientInfo = #{mountpoint := MountPoint},
+               #channel{client_info  = ClientInfo = #{mountpoint := MountPoint},
                         session = Session}) ->
     TopicFilter1 = emqx_mountpoint:mount(MountPoint, TopicFilter),
     case emqx_session:unsubscribe(ClientInfo, TopicFilter1, Session) of
@@ -506,7 +506,7 @@ do_unsubscribe(TopicFilter, _SubOpts, Channel =
 
 %%TODO: RunFold or Pipeline
 handle_out({connack, ?RC_SUCCESS, SP, ConnPkt},
-           Channel = #channel{conninfo = ConnInfo, client = ClientInfo}) ->
+           Channel = #channel{conninfo = ConnInfo, client_info = ClientInfo}) ->
     AckProps = run_fold([fun enrich_caps/2,
                          fun enrich_server_keepalive/2,
                          fun enrich_assigned_clientid/2
@@ -531,7 +531,7 @@ handle_out({connack, ?RC_SUCCESS, SP, ConnPkt},
     end;
 
 handle_out({connack, ReasonCode, _ConnPkt}, Channel = #channel{conninfo = ConnInfo,
-                                                               client   = ClientInfo}) ->
+                                                               client_info = ClientInfo}) ->
     ok = emqx_hooks:run('client.connected', [ClientInfo, ReasonCode, ConnInfo]),
     ReasonCode1 = case ProtoVer = maps:get(proto_ver, ConnInfo) of
                       ?MQTT_PROTO_V5 -> ReasonCode;
@@ -572,11 +572,11 @@ handle_out({publish, Publishes}, Channel) when is_list(Publishes) ->
 %% Ignore loop deliver
 handle_out({publish, _PacketId, #message{from  = ClientId,
                                          flags = #{nl := true}}},
-            Channel = #channel{client = #{client_id := ClientId}}) ->
+            Channel = #channel{client_info = #{client_id := ClientId}}) ->
     {ok, Channel};
 
 handle_out({publish, PacketId, Msg}, Channel =
-           #channel{client = ClientInfo = #{mountpoint := MountPoint}}) ->
+           #channel{client_info = ClientInfo = #{mountpoint := MountPoint}}) ->
     Msg1 = emqx_message:update_expiry(Msg),
     Msg2 = emqx_hooks:run_fold('message.delivered', [ClientInfo], Msg1),
     Msg3 = emqx_mountpoint:unmount(MountPoint, Msg2),
@@ -657,7 +657,7 @@ handle_call(Req, Channel) ->
 
 -spec(handle_cast(Msg :: term(), channel())
       -> ok | {ok, channel()} | {stop, Reason :: term(), channel()}).
-handle_cast({register, Attrs, Stats}, #channel{client = #{client_id := ClientId}}) ->
+handle_cast({register, Attrs, Stats}, #channel{client_info = #{client_id := ClientId}}) ->
     ok = emqx_cm:register_channel(ClientId),
     emqx_cm:set_chan_attrs(ClientId, Attrs),
     emqx_cm:set_chan_stats(ClientId, Stats);
@@ -672,14 +672,14 @@ handle_cast(Msg, Channel) ->
 
 -spec(handle_info(Info :: term(), channel())
       -> {ok, channel()} | {stop, Reason :: term(), channel()}).
-handle_info({subscribe, TopicFilters}, Channel = #channel{client = ClientInfo}) ->
+handle_info({subscribe, TopicFilters}, Channel = #channel{client_info = ClientInfo}) ->
     TopicFilters1 = emqx_hooks:run_fold('client.subscribe',
                                         [ClientInfo, #{'Internal' => true}],
                                         parse_topic_filters(TopicFilters)),
     {_ReasonCodes, NChannel} = process_subscribe(TopicFilters1, Channel),
     {ok, NChannel};
 
-handle_info({unsubscribe, TopicFilters}, Channel = #channel{client = ClientInfo}) ->
+handle_info({unsubscribe, TopicFilters}, Channel = #channel{client_info = ClientInfo}) ->
     TopicFilters1 = emqx_hooks:run_fold('client.unsubscribe',
                                         [ClientInfo, #{'Internal' => true}],
                                         parse_topic_filters(TopicFilters)),
@@ -693,7 +693,7 @@ handle_info(disconnected, Channel = #channel{connected = false}) ->
     {ok, Channel};
 
 handle_info(disconnected, Channel = #channel{conninfo = #{expiry_interval := ExpiryInterval},
-                                             client   = ClientInfo = #{zone := Zone},
+                                             client_info = ClientInfo = #{zone := Zone},
                                              will_msg = WillMsg}) ->
     emqx_zone:enable_flapping_detect(Zone) andalso emqx_flapping:detect(ClientInfo),
     Channel1 = ensure_disconnected(Channel),
@@ -726,7 +726,7 @@ handle_info(Info, Channel) ->
        | {ok, Result :: term(), channel()}
        | {stop, Reason :: term(), channel()}).
 handle_timeout(TRef, {emit_stats, Stats},
-               Channel = #channel{client = #{client_id := ClientId},
+               Channel = #channel{client_info = #{client_id := ClientId},
                                   timers = #{stats_timer := TRef}}) ->
     ok = emqx_cm:set_chan_stats(ClientId, Stats),
     {ok, clean_timer(stats_timer, Channel)};
@@ -810,7 +810,7 @@ reset_timer(Name, Time, Channel) ->
 clean_timer(Name, Channel = #channel{timers = Timers}) ->
     Channel#channel{timers = maps:remove(Name, Timers)}.
 
-interval(stats_timer, #channel{client = #{zone := Zone}}) ->
+interval(stats_timer, #channel{client_info = #{zone := Zone}}) ->
     emqx_zone:get_env(Zone, idle_timeout, 30000);
 interval(alive_timer, #channel{keepalive = KeepAlive}) ->
     emqx_keepalive:info(interval, KeepAlive);
@@ -834,12 +834,12 @@ will_delay_interval(WillMsg) ->
 
 terminate(_, #channel{connected = undefined}) ->
     ok;
-terminate(normal, #channel{conninfo = ConnInfo, client = ClientInfo}) ->
+terminate(normal, #channel{conninfo = ConnInfo, client_info = ClientInfo}) ->
     ok = emqx_hooks:run('client.disconnected', [ClientInfo, normal, ConnInfo]);
-terminate({shutdown, Reason}, #channel{conninfo = ConnInfo, client = ClientInfo})
+terminate({shutdown, Reason}, #channel{conninfo = ConnInfo, client_info = ClientInfo})
     when Reason =:= kicked orelse Reason =:= discarded orelse Reason =:= takeovered ->
     ok = emqx_hooks:run('client.disconnected', [ClientInfo, Reason, ConnInfo]);
-terminate(Reason, #channel{conninfo = ConnInfo, client = ClientInfo, will_msg = WillMsg}) ->
+terminate(Reason, #channel{conninfo = ConnInfo, client_info = ClientInfo, will_msg = WillMsg}) ->
     publish_will_msg(WillMsg),
     ok = emqx_hooks:run('client.disconnected', [ClientInfo, Reason, ConnInfo]).
 
@@ -866,7 +866,7 @@ enrich_conninfo(#mqtt_packet_connect{
                    properties  = ConnProps,
                    client_id   = ClientId,
                    username    = Username}, Channel) ->
-    #channel{conninfo = ConnInfo, client = #{zone := Zone}} = Channel,
+    #channel{conninfo = ConnInfo, client_info = #{zone := Zone}} = Channel,
     MaxInflight = emqx_mqtt_props:get('Receive-Maximum',
                                       ConnProps, emqx_zone:max_inflight(Zone)),
     Interval = if ProtoVer == ?MQTT_PROTO_V5 ->
@@ -889,18 +889,18 @@ enrich_conninfo(#mqtt_packet_connect{
     {ok, Channel#channel{conninfo = NConnInfo}}.
 
 %% @doc Check connect packet.
-check_connect(ConnPkt, #channel{client = #{zone := Zone}}) ->
+check_connect(ConnPkt, #channel{client_info = #{zone := Zone}}) ->
     emqx_packet:check(ConnPkt, emqx_mqtt_caps:get_caps(Zone)).
 
 %% @doc Enrich client
-enrich_client(ConnPkt, Channel = #channel{client = ClientInfo}) ->
+enrich_client(ConnPkt, Channel = #channel{client_info = ClientInfo}) ->
     {ok, NConnPkt, NClientInfo} =
         pipeline([fun set_username/2,
                   fun set_bridge_mode/2,
                   fun maybe_username_as_clientid/2,
                   fun maybe_assign_clientid/2,
                   fun fix_mountpoint/2], ConnPkt, ClientInfo),
-    {ok, NConnPkt, Channel#channel{client = NClientInfo}}.
+    {ok, NConnPkt, Channel#channel{client_info = NClientInfo}}.
 
 set_username(#mqtt_packet_connect{username = Username},
              ClientInfo = #{username := undefined}) ->
@@ -931,20 +931,20 @@ fix_mountpoint(_ConnPkt, ClientInfo = #{mountpoint := Mountpoint}) ->
     {ok, ClientInfo#{mountpoint := emqx_mountpoint:replvar(Mountpoint, ClientInfo)}}.
 
 %% @doc Set logger metadata.
-set_logger_meta(_ConnPkt, #channel{client = #{client_id := ClientId}}) ->
+set_logger_meta(_ConnPkt, #channel{client_info = #{client_id := ClientId}}) ->
     emqx_logger:set_metadata_client_id(ClientId).
 
 %%--------------------------------------------------------------------
 %% Check banned/flapping
 %%--------------------------------------------------------------------
 
-check_banned(_ConnPkt, #channel{client = ClientInfo = #{zone := Zone}}) ->
+check_banned(_ConnPkt, #channel{client_info = ClientInfo = #{zone := Zone}}) ->
     case emqx_zone:enable_ban(Zone) andalso emqx_banned:check(ClientInfo) of
         true  -> {error, ?RC_BANNED};
         false -> ok
     end.
 
-check_flapping(_ConnPkt, #channel{client = ClientInfo = #{zone := Zone}}) ->
+check_flapping(_ConnPkt, #channel{client_info = ClientInfo = #{zone := Zone}}) ->
     case emqx_zone:enable_flapping_detect(Zone)
          andalso emqx_flapping:check(ClientInfo) of
         true -> {error, ?RC_CONNECTION_RATE_EXCEEDED};
@@ -958,10 +958,10 @@ check_flapping(_ConnPkt, #channel{client = ClientInfo = #{zone := Zone}}) ->
 auth_connect(#mqtt_packet_connect{client_id = ClientId,
                                   username  = Username,
                                   password  = Password},
-             Channel = #channel{client = ClientInfo}) ->
+             Channel = #channel{client_info = ClientInfo}) ->
     case emqx_access_control:authenticate(ClientInfo#{password => Password}) of
         {ok, AuthResult} ->
-            {ok, Channel#channel{client = maps:merge(ClientInfo, AuthResult)}};
+            {ok, Channel#channel{client_info = maps:merge(ClientInfo, AuthResult)}};
         {error, Reason} ->
             ?LOG(warning, "Client ~s (Username: '~s') login failed for ~0p",
                  [ClientId, Username, Reason]),
@@ -1004,7 +1004,7 @@ save_alias(AliasId, Topic, Aliases) -> maps:put(AliasId, Topic, Aliases).
 
 %% Check Pub ACL
 check_pub_acl(#mqtt_packet{variable = #mqtt_packet_publish{topic_name = Topic}},
-              #channel{client = ClientInfo}) ->
+              #channel{client_info = ClientInfo}) ->
     case is_acl_enabled(ClientInfo) andalso
          emqx_access_control:check_acl(ClientInfo, publish, Topic) of
         false -> ok;
@@ -1033,7 +1033,7 @@ check_pub_caps(#mqtt_packet{header = #mqtt_packet_header{qos = QoS,
                                                          retain = Retain
                                                         }
                            },
-               #channel{client = #{zone := Zone}}) ->
+               #channel{client_info = #{zone := Zone}}) ->
     emqx_mqtt_caps:check_pub(Zone, #{qos => QoS, retain => Retain}).
 
 %% Check Sub
@@ -1044,7 +1044,7 @@ check_subscribe(TopicFilter, SubOpts, Channel) ->
     end.
 
 %% Check Sub ACL
-check_sub_acl(TopicFilter, #channel{client = ClientInfo}) ->
+check_sub_acl(TopicFilter, #channel{client_info = ClientInfo}) ->
     case is_acl_enabled(ClientInfo) andalso
          emqx_access_control:check_acl(ClientInfo, subscribe, TopicFilter) of
         false  -> allow;
@@ -1052,7 +1052,7 @@ check_sub_acl(TopicFilter, #channel{client = ClientInfo}) ->
     end.
 
 %% Check Sub Caps
-check_sub_caps(TopicFilter, SubOpts, #channel{client = #{zone := Zone}}) ->
+check_sub_caps(TopicFilter, SubOpts, #channel{client_info = #{zone := Zone}}) ->
     emqx_mqtt_caps:check_sub(Zone, TopicFilter, SubOpts).
 
 enrich_subid(#{'Subscription-Identifier' := SubId}, TopicFilters) ->
@@ -1063,12 +1063,12 @@ enrich_subid(_Properties, TopicFilters) ->
 enrich_subopts(SubOpts, #channel{conninfo = #{proto_ver := ?MQTT_PROTO_V5}}) ->
     SubOpts;
 
-enrich_subopts(SubOpts, #channel{client = #{zone := Zone, is_bridge := IsBridge}}) ->
+enrich_subopts(SubOpts, #channel{client_info = #{zone := Zone, is_bridge := IsBridge}}) ->
     NL = flag(emqx_zone:ignore_loop_deliver(Zone)),
     SubOpts#{rap => flag(IsBridge), nl => NL}.
 
 enrich_caps(AckProps, #channel{conninfo = #{proto_ver := ?MQTT_PROTO_V5},
-                               client   = #{zone := Zone}}) ->
+                               client_info = #{zone := Zone}}) ->
     #{max_packet_size       := MaxPktSize,
       max_qos_allowed       := MaxQoS,
       retain_available      := Retain,
@@ -1087,14 +1087,14 @@ enrich_caps(AckProps, #channel{conninfo = #{proto_ver := ?MQTT_PROTO_V5},
 enrich_caps(AckProps, _Channel) ->
     AckProps.
 
-enrich_server_keepalive(AckProps, #channel{client = #{zone := Zone}}) ->
+enrich_server_keepalive(AckProps, #channel{client_info = #{zone := Zone}}) ->
     case emqx_zone:server_keepalive(Zone) of
         undefined -> AckProps;
         Keepalive -> AckProps#{'Server-Keep-Alive' => Keepalive}
     end.
 
 enrich_assigned_clientid(AckProps, #channel{conninfo = ConnInfo,
-                                            client = #{client_id := ClientId}
+                                            client_info = #{client_id := ClientId}
                                            }) ->
     case maps:get(client_id, ConnInfo) of
         <<>> -> %% Original ClientId is null.
@@ -1117,7 +1117,7 @@ ensure_keepalive(_AckProps, Channel = #channel{conninfo = ConnInfo}) ->
     ensure_keepalive_timer(maps:get(keepalive, ConnInfo), Channel).
 
 ensure_keepalive_timer(0, Channel) -> Channel;
-ensure_keepalive_timer(Interval, Channel = #channel{client = #{zone := Zone}}) ->
+ensure_keepalive_timer(Interval, Channel = #channel{client_info = #{zone := Zone}}) ->
     Backoff = emqx_zone:get_env(Zone, keepalive_backoff, 0.75),
     Keepalive = emqx_keepalive:init(round(timer:seconds(Interval) * Backoff)),
     ensure_timer(alive_timer, Channel#channel{keepalive = Keepalive}).
diff --git a/src/emqx_cm.erl b/src/emqx_cm.erl
index 4da131269..80d44f4fc 100644
--- a/src/emqx_cm.erl
+++ b/src/emqx_cm.erl
@@ -162,7 +162,7 @@ set_chan_stats(ClientId, ChanPid, Stats) ->
     ok.
 
 %% @doc Open a session.
--spec(open_session(boolean(), emqx_types:client(), map())
+-spec(open_session(boolean(), emqx_types:client_info(), emqx_types:conninfo())
       -> {ok, #{session  := emqx_session:session(),
                 present  := boolean(),
                 pendings => list()}}
diff --git a/src/emqx_flapping.erl b/src/emqx_flapping.erl
index ca0e411a0..c2d2f97e2 100644
--- a/src/emqx_flapping.erl
+++ b/src/emqx_flapping.erl
@@ -69,7 +69,7 @@ start_link() ->
 stop() -> gen_server:stop(?MODULE).
 
 %% @doc Check flapping when a MQTT client connected.
--spec(check(emqx_types:client()) -> boolean()).
+-spec(check(emqx_types:client_info()) -> boolean()).
 check(#{client_id := ClientId}) ->
     check(ClientId, get_policy()).
 
@@ -81,7 +81,7 @@ check(ClientId, #{banned_interval := Interval}) ->
     end.
 
 %% @doc Detect flapping when a MQTT client disconnected.
--spec(detect(emqx_types:client()) -> boolean()).
+-spec(detect(emqx_types:client_info()) -> boolean()).
 detect(Client) -> detect(Client, get_policy()).
 
 detect(#{client_id := ClientId, peerhost := PeerHost},
diff --git a/src/emqx_mod_acl_internal.erl b/src/emqx_mod_acl_internal.erl
index 36e4f67ff..14c8d9999 100644
--- a/src/emqx_mod_acl_internal.erl
+++ b/src/emqx_mod_acl_internal.erl
@@ -61,7 +61,7 @@ all_rules() ->
 %%--------------------------------------------------------------------
 
 %% @doc Check ACL
--spec(check_acl(emqx_types:client(), emqx_types:pubsub(), emqx_topic:topic(),
+-spec(check_acl(emqx_types:client_info(), emqx_types:pubsub(), emqx_topic:topic(),
                 emqx_access_rule:acl_result(), acl_rules())
       -> {ok, allow} | {ok, deny} | ok).
 check_acl(Client, PubSub, Topic, _AclResult, Rules) ->
diff --git a/src/emqx_packet.erl b/src/emqx_packet.erl
index 6b7663b75..f1509137f 100644
--- a/src/emqx_packet.erl
+++ b/src/emqx_packet.erl
@@ -240,7 +240,7 @@ validate_topic_filters(TopicFilters) ->
       end, TopicFilters).
 
 %% @doc Publish Packet to Message.
--spec(to_message(emqx_types:client(), emqx_ypes:packet()) -> emqx_types:message()).
+-spec(to_message(emqx_types:client_info(), emqx_ypes:packet()) -> emqx_types:message()).
 to_message(#{client_id := ClientId, username := Username, peerhost := PeerHost},
            #mqtt_packet{header   = #mqtt_packet_header{type   = ?PUBLISH,
                                                        retain = Retain,
diff --git a/src/emqx_session.erl b/src/emqx_session.erl
index 434f5f5ed..7b3de773c 100644
--- a/src/emqx_session.erl
+++ b/src/emqx_session.erl
@@ -140,7 +140,7 @@
 %%--------------------------------------------------------------------
 
 %% @doc Init a session.
--spec(init(emqx_types:client(), Options :: map()) -> session()).
+-spec(init(emqx_types:client_info(), emqx_types:conninfo()) -> session()).
 init(#{zone := Zone}, #{receive_maximum := MaxInflight}) ->
     #session{max_subscriptions = get_env(Zone, max_subscriptions, 0),
              subscriptions     = #{},
@@ -252,14 +252,14 @@ redeliver(Session = #session{inflight = Inflight}) ->
 %% Client -> Broker: SUBSCRIBE
 %%--------------------------------------------------------------------
 
--spec(subscribe(emqx_types:client(), emqx_types:topic(), emqx_types:subopts(), session())
+-spec(subscribe(emqx_types:client_info(), emqx_types:topic(), emqx_types:subopts(), session())
       -> {ok, session()} | {error, emqx_types:reason_code()}).
-subscribe(Client, TopicFilter, SubOpts, Session = #session{subscriptions = Subs}) ->
+subscribe(ClientInfo, TopicFilter, SubOpts, Session = #session{subscriptions = Subs}) ->
     case is_subscriptions_full(Session)
         andalso (not maps:is_key(TopicFilter, Subs)) of
         true  -> {error, ?RC_QUOTA_EXCEEDED};
         false ->
-            do_subscribe(Client, TopicFilter, SubOpts, Session)
+            do_subscribe(ClientInfo, TopicFilter, SubOpts, Session)
     end.
 
 is_subscriptions_full(#session{max_subscriptions = 0}) ->
@@ -285,13 +285,13 @@ do_subscribe(Client = #{client_id := ClientId}, TopicFilter, SubOpts,
 %% Client -> Broker: UNSUBSCRIBE
 %%--------------------------------------------------------------------
 
--spec(unsubscribe(emqx_types:client(), emqx_types:topic(), session())
+-spec(unsubscribe(emqx_types:client_info(), emqx_types:topic(), session())
       -> {ok, session()} | {error, emqx_types:reason_code()}).
-unsubscribe(Client, TopicFilter, Session = #session{subscriptions = Subs}) ->
+unsubscribe(ClientInfo, TopicFilter, Session = #session{subscriptions = Subs}) ->
     case maps:find(TopicFilter, Subs) of
         {ok, SubOpts} ->
             ok = emqx_broker:unsubscribe(TopicFilter),
-            ok = emqx_hooks:run('session.unsubscribed', [Client, TopicFilter, SubOpts]),
+            ok = emqx_hooks:run('session.unsubscribed', [ClientInfo, TopicFilter, SubOpts]),
             {ok, Session#session{subscriptions = maps:remove(TopicFilter, Subs)}};
         error ->
             {error, ?RC_NO_SUBSCRIPTION_EXISTED}
diff --git a/src/emqx_types.erl b/src/emqx_types.erl
index 27f3c7b2e..b4e1520bf 100644
--- a/src/emqx_types.erl
+++ b/src/emqx_types.erl
@@ -32,7 +32,7 @@
              ]).
 
 -export_type([ conninfo/0
-             , client/0
+             , client_info/0
              , client_id/0
              , username/0
              , password/0
@@ -79,7 +79,6 @@
 
 -export_type([ caps/0
              , infos/0
-             , attrs/0
              , stats/0
              ]).
 
@@ -96,27 +95,29 @@
 -type(topic() :: emqx_topic:topic()).
 -type(subid() :: binary() | atom()).
 
--type(conninfo() :: #{peername := peername(),
+-type(socktype() :: tcp | udp | ssl | proxy | atom()).
+-type(conninfo() :: #{socktype := socktype(),
+                      peername := peername(),
                       sockname := peername(),
                       peercert := esockd_peercert:peercert(),
                       conn_mod := module(),
                       atom()   => term()
                      }).
--type(client() :: #{zone         := zone(),
-                    protocol     := protocol(),
-                    peerhost     := peerhost(),
-                    client_id    := client_id(),
-                    username     := username(),
-                    peercert     := esockd_peercert:peercert(),
-                    is_bridge    := boolean(),
-                    is_superuser := boolean(),
-                    mountpoint   := maybe(binary()),
-                    ws_cookie    := maybe(list()),
-                    password     => maybe(binary()),
-                    auth_result  => auth_result(),
-                    anonymous    => boolean(),
-                    atom()       => term()
-                   }).
+-type(client_info() :: #{zone         := zone(),
+                         protocol     := protocol(),
+                         peerhost     := peerhost(),
+                         client_id    := client_id(),
+                         username     := username(),
+                         peercert     := esockd_peercert:peercert(),
+                         is_bridge    := boolean(),
+                         is_superuser := boolean(),
+                         mountpoint   := maybe(binary()),
+                         ws_cookie    := maybe(list()),
+                         password     => maybe(binary()),
+                         auth_result  => auth_result(),
+                         anonymous    => boolean(),
+                         atom()       => term()
+                        }).
 -type(client_id() :: binary()|atom()).
 -type(username() :: maybe(binary())).
 -type(password() :: maybe(binary())).
@@ -167,6 +168,5 @@
 
 -type(caps() :: emqx_mqtt_caps:caps()).
 -type(infos() :: #{atom() => term()}).
--type(attrs() :: #{atom() => term()}).
--type(stats() :: list({atom(), non_neg_integer()})).
+-type(stats() :: #{atom() => non_neg_integer()|stats()}).