diff --git a/apps/emqx_modules/src/emqx_delayed.erl b/apps/emqx_modules/src/emqx_delayed.erl
index c55a8ddab..5e1754f4b 100644
--- a/apps/emqx_modules/src/emqx_delayed.erl
+++ b/apps/emqx_modules/src/emqx_delayed.erl
@@ -179,13 +179,8 @@ handle_info(Info, State) ->
 terminate(_Reason, #{timer := TRef}) ->
     emqx_misc:cancel_timer(TRef).
 
-code_change({down, Vsn}, State, _Extra) when Vsn =:= "4.3.0" ->
-    NState = maps:with([timer, publish_at], State),
-    {ok, NState};
-
-code_change(Vsn, State, _Extra) when Vsn =:= "4.3.0" ->
-    NState = ensure_stats_event(State),
-    {ok, NState}.
+code_change(_Vsn, State, _Extra) ->
+    {ok, State}.
 
 %%--------------------------------------------------------------------
 %% Internal functions
diff --git a/apps/emqx_modules/src/emqx_delayed_api.erl b/apps/emqx_modules/src/emqx_delayed_api.erl
new file mode 100644
index 000000000..06de3ab13
--- /dev/null
+++ b/apps/emqx_modules/src/emqx_delayed_api.erl
@@ -0,0 +1,182 @@
+%%--------------------------------------------------------------------
+%% Copyright (c) 2020-2021 EMQ Technologies Co., Ltd. All Rights Reserved.
+%%
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%%     http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%--------------------------------------------------------------------
+
+-module(emqx_delayed_api).
+
+-behavior(minirest_api).
+
+-import(emqx_mgmt_util, [ response_schema/1
+                        , response_schema/2
+                        , request_body_schema/1
+                        ]).
+
+% -export([cli/1]).
+
+-export([ status/2
+        , delayed_messages/2
+        , delete_delayed_message/2
+        ]).
+
+-export([enable_delayed/2]).
+
+-export([api_spec/0]).
+
+api_spec() ->
+    {[status(), delayed_messages(), delete_delayed_message()],
+     [delayed_message_schema()]}.
+
+
+delayed_message_schema() ->
+    #{broker_info => #{
+        type => object,
+        properties => #{
+            msgid => #{
+                type => string,
+                description => <<"Message Id">>
+            }
+        }
+    }}.
+
+status() ->
+    Metadata = #{
+        get => #{
+            description => "Get delayed status",
+            responses => #{
+                <<"200">> => response_schema(<<"Bad Request">>,
+                    #{
+                        type => object,
+                        properties => #{enable => #{type => boolean}}
+                    }
+                )
+            }
+        },
+        put => #{
+            description => "Enable or disbale delayed",
+            'requestBody' => request_body_schema(#{
+                type => object,
+                properties => #{
+                    enable => #{
+                        type => boolean
+                    }
+                }
+            }),
+            responses => #{
+                <<"200">> =>
+                    response_schema(<<"Enable or disbale delayed successfully">>),
+                <<"400">> =>
+                    response_schema(<<"Bad Request">>,
+                        #{
+                            type => object,
+                            properties => #{
+                                message => #{type => string},
+                                code => #{type => string}
+                            }
+                        }
+                    )
+            }
+        }
+    },
+    {"/delayed/status", Metadata, status}.
+
+delayed_messages() ->
+    Metadata = #{
+        get => #{
+            description => "Get delayed message list",
+            responses => #{
+                <<"200">> => emqx_mgmt_util:response_array_schema(<<>>, delayed_message)
+            }
+        }
+    },
+    {"/delayed/messages", Metadata, delayed_messages}.
+
+delete_delayed_message() ->
+    Metadata = #{
+        delete => #{
+            description => "Delete delayed message",
+            parameters => [#{
+                name => msgid,
+                in => path,
+                schema => #{type => string},
+                required => true
+            }],
+            responses => #{
+                <<"200">> => response_schema(<<"Bad Request">>,
+                    #{
+                        type => object,
+                        properties => #{enable => #{type => boolean}}
+                    }
+                )
+            }
+        }
+    },
+    {"/delayed/messages/:msgid", Metadata, delete_delayed_message}.
+
+
+%%--------------------------------------------------------------------
+%% HTTP API
+%%--------------------------------------------------------------------
+status(get, _Request) ->
+    {200, get_status()};
+
+status(put, Request) ->
+    {ok, Body, _} = cowboy_req:read_body(Request),
+    Params = emqx_json:decode(Body, [return_maps]),
+    Enable = maps:get(<<"enable">>, Params),
+    case Enable =:= get_status() of
+        true ->
+            Reason = case Enable of
+                true -> <<"Telemetry status is already enabled">>;
+                false -> <<"Telemetry status is already disable">>
+            end,
+            {400, #{code => "BAD_REQUEST", message => Reason}};
+        false ->
+            enable_delayed(Enable),
+             {200}
+    end.
+
+delayed_messages(get, _Request) ->
+    {200, []}.
+
+delete_delayed_message(delete, _Request) ->
+    {200}.
+
+%%--------------------------------------------------------------------
+%% internal function
+%%--------------------------------------------------------------------
+enable_delayed(Enable) ->
+    lists:foreach(fun(Node) ->
+        enable_delayed(Node, Enable)
+    end, ekka_mnesia:running_nodes()).
+
+enable_delayed(Node, Enable) when Node =:= node() ->
+    case Enable of
+        true ->
+            emqx_delayed:enable();
+        false ->
+            emqx_delayed:disable()
+    end;
+
+enable_delayed(Node, Enable) ->
+    rpc_call(Node, ?MODULE, enable_delayed, [Node, Enable]).
+
+rpc_call(Node, Module, Fun, Args) ->
+    case rpc:call(Node, Module, Fun, Args) of
+        {badrpc, Reason} -> {error, Reason};
+        Result -> Result
+    end.
+
+get_status() ->
+    emqx_config:get([delayed, enable], true).