diff --git a/.github/workflows/_push-entrypoint.yaml b/.github/workflows/_push-entrypoint.yaml
index b1ba0cdeb..e2eff6dc7 100644
--- a/.github/workflows/_push-entrypoint.yaml
+++ b/.github/workflows/_push-entrypoint.yaml
@@ -11,7 +11,7 @@ on:
       - 'e*'
     branches:
       - 'master'
-      - 'release-5?'
+      - 'release-5[0-9]'
       - 'ci/**'
 
 env:
diff --git a/apps/emqx/priv/bpapi.versions b/apps/emqx/priv/bpapi.versions
index f647c660f..7042f5186 100644
--- a/apps/emqx/priv/bpapi.versions
+++ b/apps/emqx/priv/bpapi.versions
@@ -14,7 +14,7 @@
 {emqx_conf,1}.
 {emqx_conf,2}.
 {emqx_conf,3}.
-{emqx_connector, 1}.
+{emqx_connector,1}.
 {emqx_dashboard,1}.
 {emqx_delayed,1}.
 {emqx_delayed,2}.
diff --git a/apps/emqx/src/emqx_limiter/src/emqx_limiter_schema.erl b/apps/emqx/src/emqx_limiter/src/emqx_limiter_schema.erl
index 802b29837..2dd4aa241 100644
--- a/apps/emqx/src/emqx_limiter/src/emqx_limiter_schema.erl
+++ b/apps/emqx/src/emqx_limiter/src/emqx_limiter_schema.erl
@@ -33,7 +33,7 @@
     desc/1,
     types/0,
     short_paths/0,
-    short_paths_fields/1
+    short_paths_fields/0
 ]).
 
 -define(KILOBYTE, 1024).
@@ -103,11 +103,11 @@ roots() ->
     ].
 
 fields(limiter) ->
-    short_paths_fields(?MODULE, ?IMPORTANCE_HIDDEN) ++
+    short_paths_fields(?IMPORTANCE_HIDDEN) ++
         [
             {Type,
                 ?HOCON(?R_REF(node_opts), #{
-                    desc => ?DESC(Type),
+                    desc => deprecated_desc(Type),
                     importance => ?IMPORTANCE_HIDDEN,
                     required => {false, recursively},
                     aliases => alias_of_type(Type)
@@ -120,7 +120,7 @@ fields(limiter) ->
                 ?HOCON(
                     ?R_REF(client_fields),
                     #{
-                        desc => ?DESC(client),
+                        desc => deprecated_desc(client),
                         importance => ?IMPORTANCE_HIDDEN,
                         required => {false, recursively},
                         deprecated => {since, "5.0.25"}
@@ -129,10 +129,10 @@ fields(limiter) ->
         ];
 fields(node_opts) ->
     [
-        {rate, ?HOCON(rate(), #{desc => ?DESC(rate), default => <<"infinity">>})},
+        {rate, ?HOCON(rate(), #{desc => deprecated_desc(rate), default => <<"infinity">>})},
         {burst,
             ?HOCON(burst_rate(), #{
-                desc => ?DESC(burst),
+                desc => deprecated_desc(burst),
                 default => <<"0">>
             })}
     ];
@@ -142,11 +142,12 @@ fields(bucket_opts) ->
     fields_of_bucket(<<"infinity">>);
 fields(client_opts) ->
     [
-        {rate, ?HOCON(rate(), #{default => <<"infinity">>, desc => ?DESC(rate)})},
+        {rate, ?HOCON(rate(), #{default => <<"infinity">>, desc => deprecated_desc(rate)})},
         {initial,
             ?HOCON(initial(), #{
                 default => <<"0">>,
-                desc => ?DESC(initial),
+
+                desc => deprecated_desc(initial),
                 importance => ?IMPORTANCE_HIDDEN
             })},
         %% low_watermark add for emqx_channel and emqx_session
@@ -157,14 +158,14 @@ fields(client_opts) ->
             ?HOCON(
                 initial(),
                 #{
-                    desc => ?DESC(low_watermark),
+                    desc => deprecated_desc(low_watermark),
                     default => <<"0">>,
                     importance => ?IMPORTANCE_HIDDEN
                 }
             )},
         {burst,
             ?HOCON(burst(), #{
-                desc => ?DESC(burst),
+                desc => deprecated_desc(burst),
                 default => <<"0">>,
                 importance => ?IMPORTANCE_HIDDEN,
                 aliases => [capacity]
@@ -173,7 +174,7 @@ fields(client_opts) ->
             ?HOCON(
                 boolean(),
                 #{
-                    desc => ?DESC(divisible),
+                    desc => deprecated_desc(divisible),
                     default => true,
                     importance => ?IMPORTANCE_HIDDEN
                 }
@@ -182,7 +183,7 @@ fields(client_opts) ->
             ?HOCON(
                 emqx_schema:timeout_duration(),
                 #{
-                    desc => ?DESC(max_retry_time),
+                    desc => deprecated_desc(max_retry_time),
                     default => <<"1h">>,
                     importance => ?IMPORTANCE_HIDDEN
                 }
@@ -191,7 +192,7 @@ fields(client_opts) ->
             ?HOCON(
                 failure_strategy(),
                 #{
-                    desc => ?DESC(failure_strategy),
+                    desc => deprecated_desc(failure_strategy),
                     default => force,
                     importance => ?IMPORTANCE_HIDDEN
                 }
@@ -204,14 +205,14 @@ fields(listener_client_fields) ->
 fields(Type) ->
     simple_bucket_field(Type).
 
-short_paths_fields(DesModule) ->
-    short_paths_fields(DesModule, ?DEFAULT_IMPORTANCE).
+short_paths_fields() ->
+    short_paths_fields(?DEFAULT_IMPORTANCE).
 
-short_paths_fields(DesModule, Importance) ->
+short_paths_fields(Importance) ->
     [
         {Name,
             ?HOCON(rate(), #{
-                desc => ?DESC(DesModule, Name),
+                desc => ?DESC(Name),
                 required => false,
                 importance => Importance,
                 example => Example
@@ -381,7 +382,7 @@ simple_bucket_field(Type) when is_atom(Type) ->
                 ?HOCON(
                     ?R_REF(?MODULE, client_opts),
                     #{
-                        desc => ?DESC(client),
+                        desc => deprecated_desc(client),
                         required => {false, recursively},
                         importance => importance_of_type(Type),
                         aliases => alias_of_type(Type)
@@ -394,7 +395,7 @@ composite_bucket_fields(Types, ClientRef) ->
     [
         {Type,
             ?HOCON(?R_REF(?MODULE, bucket_opts), #{
-                desc => ?DESC(?MODULE, Type),
+                desc => deprecated_desc(Type),
                 required => {false, recursively},
                 importance => importance_of_type(Type),
                 aliases => alias_of_type(Type)
@@ -406,7 +407,7 @@ composite_bucket_fields(Types, ClientRef) ->
                 ?HOCON(
                     ?R_REF(?MODULE, ClientRef),
                     #{
-                        desc => ?DESC(client),
+                        desc => deprecated_desc(client),
                         required => {false, recursively}
                     }
                 )}
@@ -414,10 +415,10 @@ composite_bucket_fields(Types, ClientRef) ->
 
 fields_of_bucket(Default) ->
     [
-        {rate, ?HOCON(rate(), #{desc => ?DESC(rate), default => Default})},
+        {rate, ?HOCON(rate(), #{desc => deprecated_desc(rate), default => Default})},
         {burst,
             ?HOCON(burst(), #{
-                desc => ?DESC(burst),
+                desc => deprecated_desc(burst),
                 default => <<"0">>,
                 importance => ?IMPORTANCE_HIDDEN,
                 aliases => [capacity]
@@ -425,7 +426,7 @@ fields_of_bucket(Default) ->
         {initial,
             ?HOCON(initial(), #{
                 default => <<"0">>,
-                desc => ?DESC(initial),
+                desc => deprecated_desc(initial),
                 importance => ?IMPORTANCE_HIDDEN
             })}
     ].
@@ -434,7 +435,7 @@ client_fields(Types) ->
     [
         {Type,
             ?HOCON(?R_REF(client_opts), #{
-                desc => ?DESC(Type),
+                desc => deprecated_desc(Type),
                 required => false,
                 importance => importance_of_type(Type),
                 aliases => alias_of_type(Type)
@@ -457,3 +458,6 @@ alias_of_type(bytes) ->
     [bytes_in];
 alias_of_type(_) ->
     [].
+
+deprecated_desc(_Field) ->
+    <<"Deprecated since v5.0.25">>.
diff --git a/apps/emqx/src/emqx_persistent_message_ds_replayer.erl b/apps/emqx/src/emqx_persistent_message_ds_replayer.erl
index d137891a2..d86ca84ad 100644
--- a/apps/emqx/src/emqx_persistent_message_ds_replayer.erl
+++ b/apps/emqx/src/emqx_persistent_message_ds_replayer.erl
@@ -28,6 +28,10 @@
 
 -include("emqx_persistent_session_ds.hrl").
 
+-ifdef(TEST).
+-include_lib("eunit/include/eunit.hrl").
+-endif.
+
 %%================================================================================
 %% Type declarations
 %%================================================================================
@@ -132,7 +136,7 @@ fetch(_SessionId, Inflight, _Streams = [], _N, Acc) ->
     {lists:reverse(Acc), Inflight};
 fetch(_SessionId, Inflight, _Streams, 0, Acc) ->
     {lists:reverse(Acc), Inflight};
-fetch(SessionId, Inflight0, [#ds_stream{stream = Stream} | Streams], N, Publishes0) ->
+fetch(SessionId, Inflight0, [Stream | Streams], N, Publishes0) ->
     #inflight{next_seqno = FirstSeqNo, offset_ranges = Ranges0} = Inflight0,
     ItBegin = get_last_iterator(SessionId, Stream, Ranges0),
     {ok, ItEnd, Messages} = emqx_ds:next(ItBegin, N),
@@ -162,6 +166,7 @@ fetch(SessionId, Inflight0, [#ds_stream{stream = Stream} | Streams], N, Publishe
             fetch(SessionId, Inflight1, Streams, N, Publishes)
     end.
 
+-spec update_iterator(emqx_persistent_session_ds:id(), emqx_ds:stream(), emqx_ds:iterator()) -> ok.
 update_iterator(SessionId, Stream, Iterator) ->
     mria:dirty_write(?SESSION_ITER_TAB, #ds_iter{id = {SessionId, Stream}, iter = Iterator}).
 
@@ -173,13 +178,20 @@ get_last_iterator(SessionId, Stream, Ranges) ->
             Next
     end.
 
+-spec get_iterator(emqx_persistent_session_ds:id(), emqx_ds:stream()) -> emqx_ds:iterator().
 get_iterator(SessionId, Stream) ->
     Id = {SessionId, Stream},
     [#ds_iter{iter = It}] = mnesia:dirty_read(?SESSION_ITER_TAB, Id),
     It.
 
+-spec get_streams(emqx_persistent_session_ds:id()) -> [emqx_ds:stream()].
 get_streams(SessionId) ->
-    mnesia:dirty_read(?SESSION_STREAM_TAB, SessionId).
+    lists:map(
+        fun(#ds_stream{stream = Stream}) ->
+            Stream
+        end,
+        mnesia:dirty_read(?SESSION_STREAM_TAB, SessionId)
+    ).
 
 %% Packet ID as defined by MQTT protocol is a 16-bit integer in range
 %% 1..FFFF. This function translates internal session sequence number
diff --git a/apps/emqx/src/emqx_persistent_session_ds.erl b/apps/emqx/src/emqx_persistent_session_ds.erl
index f3027f500..5ab7723f7 100644
--- a/apps/emqx/src/emqx_persistent_session_ds.erl
+++ b/apps/emqx/src/emqx_persistent_session_ds.erl
@@ -97,8 +97,6 @@
     props := map()
 }.
 
-%% -type session() :: #session{}.
-
 -type timestamp() :: emqx_utils_calendar:epoch_millisecond().
 -type topic() :: emqx_types:topic().
 -type clientinfo() :: emqx_types:clientinfo().
@@ -344,7 +342,15 @@ deliver(_ClientInfo, _Delivers, Session) ->
 handle_timeout(_ClientInfo, pull, Session = #{id := Id, inflight := Inflight0}) ->
     WindowSize = 100,
     {Publishes, Inflight} = emqx_persistent_message_ds_replayer:poll(Id, Inflight0, WindowSize),
-    ensure_timer(pull),
+    %% TODO: make these values configurable:
+    Timeout =
+        case Publishes of
+            [] ->
+                100;
+            [_ | _] ->
+                0
+        end,
+    ensure_timer(pull, Timeout),
     {ok, Publishes, Session#{inflight => Inflight}};
 handle_timeout(_ClientInfo, get_streams, Session = #{id := Id}) ->
     renew_streams(Id),
@@ -714,5 +720,9 @@ ensure_timers() ->
 
 -spec ensure_timer(pull | get_streams) -> ok.
 ensure_timer(Type) ->
-    _ = emqx_utils:start_timer(100, {emqx_session, Type}),
+    ensure_timer(Type, 100).
+
+-spec ensure_timer(pull | get_streams, non_neg_integer()) -> ok.
+ensure_timer(Type, Timeout) ->
+    _ = emqx_utils:start_timer(Timeout, {emqx_session, Type}),
     ok.
diff --git a/apps/emqx/src/emqx_persistent_session_ds.hrl b/apps/emqx/src/emqx_persistent_session_ds.hrl
index 54b077795..81b997df5 100644
--- a/apps/emqx/src/emqx_persistent_session_ds.hrl
+++ b/apps/emqx/src/emqx_persistent_session_ds.hrl
@@ -36,6 +36,7 @@
     stream :: emqx_ds:stream(),
     rank :: emqx_ds:stream_rank()
 }).
+-type ds_stream() :: #ds_stream{}.
 
 -record(ds_iter, {
     id :: {emqx_persistent_session_ds:id(), emqx_ds:stream()},
diff --git a/apps/emqx/src/emqx_schema.erl b/apps/emqx/src/emqx_schema.erl
index 804a3a04c..3848e77b4 100644
--- a/apps/emqx/src/emqx_schema.erl
+++ b/apps/emqx/src/emqx_schema.erl
@@ -1849,7 +1849,7 @@ base_listener(Bind) ->
                     default => true
                 }
             )}
-    ] ++ emqx_limiter_schema:short_paths_fields(?MODULE).
+    ] ++ emqx_limiter_schema:short_paths_fields().
 
 desc("persistent_session_store") ->
     "Settings for message persistence.";
diff --git a/apps/emqx/test/emqx_cm_SUITE.erl b/apps/emqx/test/emqx_cm_SUITE.erl
index 6afdfa478..9bfb4d5e7 100644
--- a/apps/emqx/test/emqx_cm_SUITE.erl
+++ b/apps/emqx/test/emqx_cm_SUITE.erl
@@ -306,7 +306,7 @@ test_stepdown_session(Action, Reason) ->
     ok = emqx_cm:register_channel(ClientId, Pid1, ConnInfo),
     ok = emqx_cm:register_channel(ClientId, Pid1, ConnInfo),
     ok = emqx_cm:register_channel(ClientId, Pid2, ConnInfo),
-    ?assertEqual([Pid1, Pid2], lists:sort(emqx_cm:lookup_channels(ClientId))),
+    ?assertEqual(lists:sort([Pid1, Pid2]), lists:sort(emqx_cm:lookup_channels(ClientId))),
     case Reason of
         noproc ->
             exit(Pid1, kill),
diff --git a/apps/emqx_durable_storage/src/emqx_ds_replication_layer.erl b/apps/emqx_durable_storage/src/emqx_ds_replication_layer.erl
index d61dfa906..b81f43c4f 100644
--- a/apps/emqx_durable_storage/src/emqx_ds_replication_layer.erl
+++ b/apps/emqx_durable_storage/src/emqx_ds_replication_layer.erl
@@ -43,30 +43,41 @@
 %% Type declarations
 %%================================================================================
 
+%% # "Record" integer keys.  We use maps with integer keys to avoid persisting and sending
+%% records over the wire.
+
+%% tags:
+-define(stream, stream).
+-define(it, it).
+
+%% keys:
+-define(tag, 1).
+-define(shard, 2).
+-define(enc, 3).
+
 -type db() :: emqx_ds:db().
 
 -type shard_id() :: {db(), atom()}.
 
-%% This record enapsulates the stream entity from the replication
-%% level.
+%% This enapsulates the stream entity from the replication level.
 %%
 %% TODO: currently the stream is hardwired to only support the
 %% internal rocksdb storage. In the future we want to add another
 %% implementations for emqx_ds, so this type has to take this into
 %% account.
--record(stream, {
-    shard :: emqx_ds_replication_layer:shard_id(),
-    enc :: emqx_ds_storage_layer:stream()
-}).
+-opaque stream() ::
+    #{
+        ?tag := ?stream,
+        ?shard := emqx_ds_replication_layer:shard_id(),
+        ?enc := emqx_ds_storage_layer:stream()
+    }.
 
--opaque stream() :: #stream{}.
-
--record(iterator, {
-    shard :: emqx_ds_replication_layer:shard_id(),
-    enc :: enqx_ds_storage_layer:iterator()
-}).
-
--opaque iterator() :: #iterator{}.
+-opaque iterator() ::
+    #{
+        ?tag := ?it,
+        ?shard := emqx_ds_replication_layer:shard_id(),
+        ?enc := emqx_ds_storage_layer:iterator()
+    }.
 
 -type message_id() :: emqx_ds_storage_layer:message_id().
 
@@ -124,9 +135,10 @@ get_streams(DB, TopicFilter, StartTime) ->
                 fun({RankY, Stream}) ->
                     RankX = Shard,
                     Rank = {RankX, RankY},
-                    {Rank, #stream{
-                        shard = Shard,
-                        enc = Stream
+                    {Rank, #{
+                        ?tag => ?stream,
+                        ?shard => Shard,
+                        ?enc => Stream
                     }}
                 end,
                 Streams
@@ -138,18 +150,18 @@ get_streams(DB, TopicFilter, StartTime) ->
 -spec make_iterator(stream(), emqx_ds:topic_filter(), emqx_ds:time()) ->
     emqx_ds:make_iterator_result(iterator()).
 make_iterator(Stream, TopicFilter, StartTime) ->
-    #stream{shard = Shard, enc = StorageStream} = Stream,
+    #{?tag := ?stream, ?shard := Shard, ?enc := StorageStream} = Stream,
     Node = node_of_shard(Shard),
     case emqx_ds_proto_v1:make_iterator(Node, Shard, StorageStream, TopicFilter, StartTime) of
         {ok, Iter} ->
-            {ok, #iterator{shard = Shard, enc = Iter}};
+            {ok, #{?tag => ?it, ?shard => Shard, ?enc => Iter}};
         Err = {error, _} ->
             Err
     end.
 
 -spec next(iterator(), pos_integer()) -> emqx_ds:next_result(iterator()).
 next(Iter0, BatchSize) ->
-    #iterator{shard = Shard, enc = StorageIter0} = Iter0,
+    #{?tag := ?it, ?shard := Shard, ?enc := StorageIter0} = Iter0,
     Node = node_of_shard(Shard),
     %% TODO: iterator can contain information that is useful for
     %% reconstructing messages sent over the network. For example,
@@ -161,7 +173,7 @@ next(Iter0, BatchSize) ->
     %% replication layer. Or, perhaps, in the logic layer.
     case emqx_ds_proto_v1:next(Node, Shard, StorageIter0, BatchSize) of
         {ok, StorageIter, Batch} ->
-            Iter = #iterator{shard = Shard, enc = StorageIter},
+            Iter = Iter0#{?enc := StorageIter},
             {ok, Iter, Batch};
         Other ->
             Other
@@ -184,14 +196,14 @@ do_drop_shard_v1(Shard) ->
     emqx_ds_storage_layer:drop_shard(Shard).
 
 -spec do_get_streams_v1(shard_id(), emqx_ds:topic_filter(), emqx_ds:time()) ->
-    [{integer(), _Stream}].
+    [{integer(), emqx_ds_storage_layer:stream()}].
 do_get_streams_v1(Shard, TopicFilter, StartTime) ->
     emqx_ds_storage_layer:get_streams(Shard, TopicFilter, StartTime).
 
 -spec do_make_iterator_v1(
     shard_id(), emqx_ds_storage_layer:stream(), emqx_ds:topic_filter(), emqx_ds:time()
 ) ->
-    {ok, iterator()} | {error, _}.
+    {ok, emqx_ds_storage_layer:iterator()} | {error, _}.
 do_make_iterator_v1(Shard, Stream, TopicFilter, StartTime) ->
     emqx_ds_storage_layer:make_iterator(Shard, Stream, TopicFilter, StartTime).
 
diff --git a/apps/emqx_durable_storage/src/emqx_ds_storage_bitfield_lts.erl b/apps/emqx_durable_storage/src/emqx_ds_storage_bitfield_lts.erl
index d57d8013c..d2c997ae1 100644
--- a/apps/emqx_durable_storage/src/emqx_ds_storage_bitfield_lts.erl
+++ b/apps/emqx_durable_storage/src/emqx_ds_storage_bitfield_lts.erl
@@ -38,6 +38,20 @@
 %% Type declarations
 %%================================================================================
 
+%% # "Record" integer keys.  We use maps with integer keys to avoid persisting and sending
+%% records over the wire.
+
+%% tags:
+-define(stream, stream).
+-define(it, it).
+
+%% keys:
+-define(tag, 1).
+-define(topic_filter, 2).
+-define(start_time, 3).
+-define(storage_key, 4).
+-define(last_seen_key, 5).
+
 -type options() ::
     #{
         bits_per_wildcard_level => pos_integer(),
@@ -65,18 +79,20 @@
 
 -type s() :: #s{}.
 
--record(stream, {
-    storage_key :: emqx_ds_lts:msg_storage_key()
-}).
+-type stream() ::
+    #{
+        ?tag := ?stream,
+        ?storage_key := emqx_ds_lts:msg_storage_key()
+    }.
 
--record(it, {
-    topic_filter :: emqx_ds:topic_filter(),
-    start_time :: emqx_ds:time(),
-    storage_key :: emqx_ds_lts:msg_storage_key(),
-    last_seen_key = <<>> :: binary()
-}).
-
--type iterator() :: #it{}.
+-type iterator() ::
+    #{
+        ?tag := ?it,
+        ?topic_filter := emqx_ds:topic_filter(),
+        ?start_time := emqx_ds:time(),
+        ?storage_key := emqx_ds_lts:msg_storage_key(),
+        ?last_seen_key := binary()
+    }.
 
 -define(COUNTER, emqx_ds_storage_bitfield_lts_counter).
 
@@ -170,18 +186,35 @@ store_batch(_ShardId, S = #s{db = DB, data = Data}, Messages, _Options) ->
         Messages
     ).
 
+-spec get_streams(
+    emqx_ds_replication_layer:shard_id(),
+    s(),
+    emqx_ds:topic_filter(),
+    emqx_ds:time()
+) -> [stream()].
 get_streams(_Shard, #s{trie = Trie}, TopicFilter, _StartTime) ->
     Indexes = emqx_ds_lts:match_topics(Trie, TopicFilter),
-    [#stream{storage_key = I} || I <- Indexes].
+    [#{?tag => ?stream, ?storage_key => I} || I <- Indexes].
 
-make_iterator(_Shard, _Data, #stream{storage_key = StorageKey}, TopicFilter, StartTime) ->
+-spec make_iterator(
+    emqx_ds_replication_layer:shard_id(),
+    s(),
+    stream(),
+    emqx_ds:topic_filter(),
+    emqx_ds:time()
+) -> {ok, iterator()}.
+make_iterator(
+    _Shard, _Data, #{?tag := ?stream, ?storage_key := StorageKey}, TopicFilter, StartTime
+) ->
     %% Note: it's a good idea to keep the iterator structure lean,
     %% since it can be stored on a remote node that could update its
     %% code independently from us.
-    {ok, #it{
-        topic_filter = TopicFilter,
-        start_time = StartTime,
-        storage_key = StorageKey
+    {ok, #{
+        ?tag => ?it,
+        ?topic_filter => TopicFilter,
+        ?start_time => StartTime,
+        ?storage_key => StorageKey,
+        ?last_seen_key => <<>>
     }}.
 
 next(_Shard, Schema = #s{ts_offset = TSOffset}, It, BatchSize) ->
@@ -192,16 +225,19 @@ next(_Shard, Schema = #s{ts_offset = TSOffset}, It, BatchSize) ->
     SafeCutoffTime = (Now bsr TSOffset) bsl TSOffset,
     next_until(Schema, It, SafeCutoffTime, BatchSize).
 
-next_until(_Schema, It, SafeCutoffTime, _BatchSize) when It#it.start_time >= SafeCutoffTime ->
+next_until(_Schema, It = #{?tag := ?it, ?start_time := StartTime}, SafeCutoffTime, _BatchSize) when
+    StartTime >= SafeCutoffTime
+->
     %% We're in the middle of the current epoch, so we can't yet iterate over it.
     %% It would be unsafe otherwise: messages can be stored in the current epoch
     %% concurrently with iterating over it. They can end up earlier (in the iteration
     %% order) due to the nature of keymapping, potentially causing us to miss them.
     {ok, It, []};
 next_until(#s{db = DB, data = CF, keymappers = Keymappers}, It, SafeCutoffTime, BatchSize) ->
-    #it{
-        start_time = StartTime,
-        storage_key = {TopicIndex, Varying}
+    #{
+        ?tag := ?it,
+        ?start_time := StartTime,
+        ?storage_key := {TopicIndex, Varying}
     } = It,
     %% Make filter:
     Inequations = [
@@ -250,7 +286,7 @@ next_loop(_ITHandle, _KeyMapper, _Filter, _Cutoff, It, Acc, 0) ->
     {ok, It, lists:reverse(Acc)};
 next_loop(ITHandle, KeyMapper, Filter, Cutoff, It0, Acc0, N0) ->
     inc_counter(),
-    #it{last_seen_key = Key0} = It0,
+    #{?tag := ?it, ?last_seen_key := Key0} = It0,
     case emqx_ds_bitmask_keymapper:bin_increment(Filter, Key0) of
         overflow ->
             {ok, It0, lists:reverse(Acc0)};
@@ -268,7 +304,7 @@ next_loop(ITHandle, KeyMapper, Filter, Cutoff, It0, Acc0, N0) ->
     end.
 
 traverse_interval(ITHandle, Filter, Cutoff, Key, Val, It0, Acc0, N) ->
-    It = It0#it{last_seen_key = Key},
+    It = It0#{?last_seen_key := Key},
     case emqx_ds_bitmask_keymapper:bin_checkmask(Filter, Key) of
         true ->
             Msg = deserialize(Val),
@@ -310,7 +346,7 @@ check_message(
     overflow;
 check_message(
     _Cutoff,
-    #it{start_time = StartTime, topic_filter = TopicFilter},
+    #{?tag := ?it, ?start_time := StartTime, ?topic_filter := TopicFilter},
     #message{timestamp = Timestamp, topic = Topic}
 ) when Timestamp >= StartTime ->
     emqx_topic:match(emqx_topic:words(Topic), TopicFilter);
diff --git a/apps/emqx_durable_storage/src/emqx_ds_storage_layer.erl b/apps/emqx_durable_storage/src/emqx_ds_storage_layer.erl
index 57af33d61..c91ac49d5 100644
--- a/apps/emqx_durable_storage/src/emqx_ds_storage_layer.erl
+++ b/apps/emqx_durable_storage/src/emqx_ds_storage_layer.erl
@@ -34,6 +34,18 @@
 %% Type declarations
 %%================================================================================
 
+%% # "Record" integer keys.  We use maps with integer keys to avoid persisting and sending
+%% records over the wire.
+
+%% tags:
+-define(stream, stream).
+-define(it, it).
+
+%% keys:
+-define(tag, 1).
+-define(generation, 2).
+-define(enc, 3).
+
 -type prototype() ::
     {emqx_ds_storage_reference, emqx_ds_storage_reference:options()}
     | {emqx_ds_storage_bitfield_lts, emqx_ds_storage_bitfield_lts:options()}.
@@ -44,23 +56,21 @@
 
 -type gen_id() :: 0..16#ffff.
 
-%% Note: this record might be stored permanently on a remote node.
--record(stream, {
-    generation :: gen_id(),
-    enc :: _EncapsulatedData,
-    misc = #{} :: map()
-}).
+%% Note: this might be stored permanently on a remote node.
+-opaque stream() ::
+    #{
+        ?tag := ?stream,
+        ?generation := gen_id(),
+        ?enc := term()
+    }.
 
--opaque stream() :: #stream{}.
-
-%% Note: this record might be stored permanently on a remote node.
--record(it, {
-    generation :: gen_id(),
-    enc :: _EncapsulatedData,
-    misc = #{} :: map()
-}).
-
--opaque iterator() :: #it{}.
+%% Note: this might be stored permanently on a remote node.
+-opaque iterator() ::
+    #{
+        ?tag := ?it,
+        ?generation := gen_id(),
+        ?enc := term()
+    }.
 
 %%%% Generation:
 
@@ -154,9 +164,10 @@ get_streams(Shard, TopicFilter, StartTime) ->
             #{module := Mod, data := GenData} = generation_get(Shard, GenId),
             Streams = Mod:get_streams(Shard, GenData, TopicFilter, StartTime),
             [
-                {GenId, #stream{
-                    generation = GenId,
-                    enc = Stream
+                {GenId, #{
+                    ?tag => ?stream,
+                    ?generation => GenId,
+                    ?enc => Stream
                 }}
              || Stream <- Streams
             ]
@@ -166,13 +177,16 @@ get_streams(Shard, TopicFilter, StartTime) ->
 
 -spec make_iterator(shard_id(), stream(), emqx_ds:topic_filter(), emqx_ds:time()) ->
     emqx_ds:make_iterator_result(iterator()).
-make_iterator(Shard, #stream{generation = GenId, enc = Stream}, TopicFilter, StartTime) ->
+make_iterator(
+    Shard, #{?tag := ?stream, ?generation := GenId, ?enc := Stream}, TopicFilter, StartTime
+) ->
     #{module := Mod, data := GenData} = generation_get(Shard, GenId),
     case Mod:make_iterator(Shard, GenData, Stream, TopicFilter, StartTime) of
         {ok, Iter} ->
-            {ok, #it{
-                generation = GenId,
-                enc = Iter
+            {ok, #{
+                ?tag => ?it,
+                ?generation => GenId,
+                ?enc => Iter
             }};
         {error, _} = Err ->
             Err
@@ -180,7 +194,7 @@ make_iterator(Shard, #stream{generation = GenId, enc = Stream}, TopicFilter, Sta
 
 -spec next(shard_id(), iterator(), pos_integer()) ->
     emqx_ds:next_result(iterator()).
-next(Shard, Iter = #it{generation = GenId, enc = GenIter0}, BatchSize) ->
+next(Shard, Iter = #{?tag := ?it, ?generation := GenId, ?enc := GenIter0}, BatchSize) ->
     #{module := Mod, data := GenData} = generation_get(Shard, GenId),
     Current = generation_current(Shard),
     case Mod:next(Shard, GenData, GenIter0, BatchSize) of
@@ -190,7 +204,7 @@ next(Shard, Iter = #it{generation = GenId, enc = GenIter0}, BatchSize) ->
             %% the stream has been fully replayed.
             {ok, end_of_stream};
         {ok, GenIter, Batch} ->
-            {ok, Iter#it{enc = GenIter}, Batch};
+            {ok, Iter#{?enc := GenIter}, Batch};
         Error = {error, _} ->
             Error
     end.
diff --git a/apps/emqx_durable_storage/src/proto/emqx_ds_proto_v1.erl b/apps/emqx_durable_storage/src/proto/emqx_ds_proto_v1.erl
index 17e873ecd..6a79a4a61 100644
--- a/apps/emqx_durable_storage/src/proto/emqx_ds_proto_v1.erl
+++ b/apps/emqx_durable_storage/src/proto/emqx_ds_proto_v1.erl
@@ -41,7 +41,7 @@ drop_shard(Node, Shard) ->
 -spec get_streams(
     node(), emqx_ds_replication_layer:shard_id(), emqx_ds:topic_filter(), emqx_ds:time()
 ) ->
-    [{integer(), emqx_ds_replication_layer:stream()}].
+    [{integer(), emqx_ds_storage_layer:stream()}].
 get_streams(Node, Shard, TopicFilter, Time) ->
     erpc:call(Node, emqx_ds_replication_layer, do_get_streams_v1, [Shard, TopicFilter, Time]).
 
@@ -52,7 +52,7 @@ get_streams(Node, Shard, TopicFilter, Time) ->
     emqx_ds:topic_filter(),
     emqx_ds:time()
 ) ->
-    {ok, emqx_ds_replication_layer:iterator()} | {error, _}.
+    {ok, emqx_ds_storage_layer:iterator()} | {error, _}.
 make_iterator(Node, Shard, Stream, TopicFilter, StartTime) ->
     erpc:call(Node, emqx_ds_replication_layer, do_make_iterator_v1, [
         Shard, Stream, TopicFilter, StartTime
diff --git a/rel/i18n/emqx_limiter_schema.hocon b/rel/i18n/emqx_limiter_schema.hocon
index b2958ce90..1a0ed5273 100644
--- a/rel/i18n/emqx_limiter_schema.hocon
+++ b/rel/i18n/emqx_limiter_schema.hocon
@@ -2,114 +2,33 @@ emqx_limiter_schema {
 
 max_conn_rate.desc:
 """Maximum connection rate.<br/>
-This is used to limit the connection rate for this node,
-once the limit is reached, new connections will be deferred or refused"""
+This is used to limit the connection rate for this node.
+Once the limit is reached, new connections will be deferred or refused.<br/>
+For example:<br/>
+- <code>1000/s</code> :: Only accepts 1000 connections per second<br/>
+- <code>1000/10s</code> :: Only accepts 1000 connections every 10 seconds"""
 max_conn_rate.label:
 """Maximum Connection Rate"""
 
 messages_rate.desc:
 """Messages publish rate.<br/>
-This is used to limit the inbound message numbers for this node,
-once the limit is reached, the restricted client will slow down and even be hung for a while."""
+This is used to limit the inbound message numbers for this node.
+Once the limit is reached, the restricted client will slow down and even be hung for a while.<br/>
+For example:<br/>
+- <code>500/s</code> :: Only the first 500 messages are sent per second and other messages are buffered.<br/>
+- <code>500/10s</code> :: Only the first 500 messages are sent even 10 second and other messages are buffered."""
 messages_rate.label:
 """Messages Publish Rate"""
 
 bytes_rate.desc:
 """Data publish rate.<br/>
-This is used to limit the inbound bytes rate for this node,
-once the limit is reached, the restricted client will slow down and even be hung for a while."""
+This is used to limit the inbound bytes rate for this node.
+Once the limit is reached, the restricted client will slow down and even be hung for a while.<br/>
+The unit of the bytes could be:KB MB GB.<br/>
+For example:<br/>
+- <code>500KB/s</code> :: Only the first 500 kilobytes are sent per second and other messages are buffered.<br/>
+- <code>500MB/10s</code> :: Only the first 500 megabytes are sent even 10 second and other messages are buffered."""
 bytes_rate.label:
 """Data Publish Rate"""
 
-bucket_cfg.desc:
-"""Bucket Configs"""
-
-bucket_cfg.label:
-"""Buckets"""
-
-burst.desc:
-"""The burst, This value is based on rate.<br/>
- This value + rate = the maximum limit that can be achieved when limiter burst."""
-
-burst.label:
-"""Burst"""
-
-bytes.desc:
-"""The `bytes` limiter.
-This is used to limit the inbound bytes rate for this EMQX node.
-Once the limit is reached, the restricted client will be slow down even be hung for a while."""
-
-bytes.label:
-"""Bytes"""
-
-client.desc:
-"""The rate limit for each user of the bucket"""
-
-client.label:
-"""Per Client"""
-
-connection.desc:
-"""The connection limiter.
-This is used to limit the connection rate for this EMQX node.
-Once the limit is reached, new connections will be refused"""
-
-connection.label:
-"""Connection"""
-
-divisible.desc:
-"""Is it possible to split the number of requested tokens?"""
-
-divisible.label:
-"""Divisible"""
-
-failure_strategy.desc:
-"""The strategy when all the retries failed."""
-
-failure_strategy.label:
-"""Failure Strategy"""
-
-initial.desc:
-"""The initial number of tokens for this bucket."""
-
-initial.label:
-"""Initial"""
-
-internal.desc:
-"""Limiter for EMQX internal app."""
-
-low_watermark.desc:
-"""If the remaining tokens are lower than this value,
-the check/consume will succeed, but it will be forced to wait for a short period of time."""
-
-low_watermark.label:
-"""Low Watermark"""
-
-max_retry_time.desc:
-"""The maximum retry time when acquire failed."""
-
-max_retry_time.label:
-"""Max Retry Time"""
-
-message_routing.desc:
-"""The message routing limiter.
-This is used to limit the forwarding rate for this EMQX node.
-Once the limit is reached, new publish will be refused"""
-
-message_routing.label:
-"""Message Routing"""
-
-messages.desc:
-"""The `messages` limiter.
-This is used to limit the inbound message numbers for this EMQX node
-Once the limit is reached, the restricted client will be slow down even be hung for a while."""
-
-messages.label:
-"""Messages"""
-
-rate.desc:
-"""Rate for this bucket."""
-
-rate.label:
-"""Rate"""
-
 }
diff --git a/rel/i18n/emqx_schema.hocon b/rel/i18n/emqx_schema.hocon
index 9ed579994..e1d086197 100644
--- a/rel/i18n/emqx_schema.hocon
+++ b/rel/i18n/emqx_schema.hocon
@@ -1039,27 +1039,6 @@ base_listener_limiter.desc:
 base_listener_limiter.label:
 """Type of the rate limit."""
 
-max_conn_rate.desc:
-"""Maximum connection rate.<br/>
-This is used to limit the connection rate for this listener,
-once the limit is reached, new connections will be deferred or refused"""
-max_conn_rate.label:
-"""Maximum Connection Rate"""
-
-messages_rate.desc:
-"""Messages publish rate.<br/>
-This is used to limit the inbound message numbers for each client connected to this listener,
-once the limit is reached, the restricted client will slow down and even be hung for a while."""
-messages_rate.label:
-"""Messages Publish Rate"""
-
-bytes_rate.desc:
-"""Data publish rate.<br/>
-This is used to limit the inbound bytes rate for each client connected to this listener,
-once the limit is reached, the restricted client will slow down and even be hung for a while."""
-bytes_rate.label:
-"""Data Publish Rate"""
-
 persistent_session_store_backend.desc:
 """Database management system used to store information about persistent sessions and messages.
 - `builtin`: Use the embedded database (mria)"""