diff --git a/apps/emqx_gateway/src/coap/emqx_coap_channel.erl b/apps/emqx_gateway/src/coap/emqx_coap_channel.erl
index efffabee3..bfd505750 100644
--- a/apps/emqx_gateway/src/coap/emqx_coap_channel.erl
+++ b/apps/emqx_gateway/src/coap/emqx_coap_channel.erl
@@ -232,8 +232,9 @@ handle_call({subscribe, _Topic, _SubOpts}, _From, Channel) ->
 handle_call({unsubscribe, _Topic}, _From, Channel) ->
     {reply, {error, noimpl}, Channel};
 
-handle_call(subscriptions, _From, Channel) ->
-    {reply, {error, noimpl}, Channel};
+handle_call(subscriptions, _From, Channel = #channel{session = Session}) ->
+    Subs = emqx_coap_session:info(subscriptions, Session),
+    {reply, {ok, maps:to_list(Subs)}, Channel};
 
 handle_call(kick, _From, Channel) ->
     NChannel = ensure_disconnected(kicked, Channel),
diff --git a/apps/emqx_gateway/src/coap/emqx_coap_observe_res.erl b/apps/emqx_gateway/src/coap/emqx_coap_observe_res.erl
index 20473322e..dbec52d2b 100644
--- a/apps/emqx_gateway/src/coap/emqx_coap_observe_res.erl
+++ b/apps/emqx_gateway/src/coap/emqx_coap_observe_res.erl
@@ -23,7 +23,6 @@
 
 -define(MAX_SEQ_ID, 16777215).
 
--type topic() :: binary().
 -type token() :: binary().
 -type seq_id() :: 0 .. ?MAX_SEQ_ID.
 
@@ -31,7 +30,7 @@
                 , seq_id := seq_id()
                 }.
 
--type manager() :: #{topic => res()}.
+-type manager() :: #{emqx_types:topic() => res()}.
 
 %%--------------------------------------------------------------------
 %% API
@@ -40,7 +39,7 @@
 new_manager() ->
     #{}.
 
--spec insert(topic(), token(), manager()) -> {seq_id(), manager()}.
+-spec insert(emqx_types:topic(), token(), manager()) -> {seq_id(), manager()}.
 insert(Topic, Token, Manager) ->
     Res = case maps:get(Topic, Manager, undefined) of
               undefined ->
@@ -50,11 +49,11 @@ insert(Topic, Token, Manager) ->
           end,
     {maps:get(seq_id, Res), Manager#{Topic => Res}}.
 
--spec remove(topic(), manager()) -> manager().
+-spec remove(emqx_types:topic(), manager()) -> manager().
 remove(Topic, Manager) ->
     maps:remove(Topic, Manager).
 
--spec res_changed(topic(), manager()) -> undefined | {token(), seq_id(), manager()}.
+-spec res_changed(emqx_types:topic(), manager()) -> undefined | {token(), seq_id(), manager()}.
 res_changed(Topic, Manager) ->
     case maps:get(Topic, Manager, undefined) of
         undefined ->
@@ -73,6 +72,7 @@ foreach(F, Manager) ->
               Manager),
     ok.
 
+-spec subscriptions(manager()) -> [emqx_types:topic()].
 subscriptions(Manager) ->
     maps:keys(Manager).
 
diff --git a/apps/emqx_gateway/src/coap/emqx_coap_session.erl b/apps/emqx_gateway/src/coap/emqx_coap_session.erl
index f94b4e9b3..9c3a8c451 100644
--- a/apps/emqx_gateway/src/coap/emqx_coap_session.erl
+++ b/apps/emqx_gateway/src/coap/emqx_coap_session.erl
@@ -91,7 +91,8 @@ info(Session) ->
 info(Keys, Session) when is_list(Keys) ->
     [{Key, info(Key, Session)} || Key <- Keys];
 info(subscriptions, #session{observe_manager = OM}) ->
-    emqx_coap_observe_res:subscriptions(OM);
+    Topics = emqx_coap_observe_res:subscriptions(OM),
+    lists:foldl(fun(T, Acc) -> Acc#{T => ?DEFAULT_SUBOPTS} end, #{}, Topics);
 info(subscriptions_cnt, #session{observe_manager = OM}) ->
     erlang:length(emqx_coap_observe_res:subscriptions(OM));
 info(subscriptions_max, _) ->
diff --git a/apps/emqx_gateway/src/exproto/emqx_exproto_channel.erl b/apps/emqx_gateway/src/exproto/emqx_exproto_channel.erl
index 58b497cfc..bb72d24e6 100644
--- a/apps/emqx_gateway/src/exproto/emqx_exproto_channel.erl
+++ b/apps/emqx_gateway/src/exproto/emqx_exproto_channel.erl
@@ -351,6 +351,9 @@ handle_call({unsubscribe, Topic}, _From, Channel) ->
     {ok, NChannel} = do_unsubscribe([Topic], Channel),
     {reply, ok, NChannel};
 
+handle_call(subscriptions, _From, Channel = #channel{subscriptions = Subs}) ->
+    {reply, {ok, maps:to_list(Subs)}, Channel};
+
 handle_call({publish, Topic, Qos, Payload}, _From,
             Channel = #channel{
                          ctx = Ctx,
@@ -369,7 +372,10 @@ handle_call({publish, Topic, Qos, Payload}, _From,
     end;
 
 handle_call(kick, _From, Channel) ->
-    {shutdown, kicked, ok, Channel};
+    {shutdown, kicked, ok, ensure_disconnected(kicked, Channel)};
+
+handle_call(discard, _From, Channel) ->
+    {shutdown, discarded, ok, Channel};
 
 handle_call(Req, _From, Channel) ->
     ?SLOG(warning, #{ msg => "unexpected_call"
diff --git a/apps/emqx_gateway/src/mqttsn/emqx_sn_channel.erl b/apps/emqx_gateway/src/mqttsn/emqx_sn_channel.erl
index f9cfa3cbe..0b1bdde73 100644
--- a/apps/emqx_gateway/src/mqttsn/emqx_sn_channel.erl
+++ b/apps/emqx_gateway/src/mqttsn/emqx_sn_channel.erl
@@ -1214,7 +1214,7 @@ handle_call({unsubscribe, Topic}, _From, Channel) ->
     reply(ok, NChannel);
 
 handle_call(subscriptions, _From, Channel = #channel{session = Session}) ->
-    reply(maps:to_list(emqx_session:info(subscriptions, Session)), Channel);
+    reply({ok, maps:to_list(emqx_session:info(subscriptions, Session))}, Channel);
 
 handle_call(kick, _From, Channel) ->
     NChannel = ensure_disconnected(kicked, Channel),
diff --git a/apps/emqx_gateway/src/stomp/emqx_stomp_channel.erl b/apps/emqx_gateway/src/stomp/emqx_stomp_channel.erl
index 48cef70f8..17a7644ec 100644
--- a/apps/emqx_gateway/src/stomp/emqx_stomp_channel.erl
+++ b/apps/emqx_gateway/src/stomp/emqx_stomp_channel.erl
@@ -688,11 +688,11 @@ handle_call({unsubscribe, Topic}, _From,
 
 %% Reply :: [{emqx_types:topic(), emqx_types:subopts()}]
 handle_call(subscriptions, _From, Channel = #channel{subscriptions = Subs}) ->
-    Reply = lists:map(
+    NSubs = lists:map(
               fun({_SubId, Topic, _Ack, SubOpts}) ->
                 {Topic, SubOpts}
               end, Subs),
-    reply(Reply, Channel);
+    reply({ok, NSubs}, Channel);
 
 handle_call(kick, _From, Channel) ->
     NChannel = ensure_disconnected(kicked, Channel),