diff --git a/apps/emqx/src/emqx_session.erl b/apps/emqx/src/emqx_session.erl
index c08109fe8..7604c2ba5 100644
--- a/apps/emqx/src/emqx_session.erl
+++ b/apps/emqx/src/emqx_session.erl
@@ -175,11 +175,19 @@
 %% Behaviour
 %% -------------------------------------------------------------------
 
+-if(?OTP_RELEASE < 26).
+-callback create(clientinfo(), conninfo(), conf()) ->
+    term().
+-callback open(clientinfo(), conninfo(), conf()) ->
+    term().
+-callback destroy(t() | clientinfo()) -> ok.
+-else.
 -callback create(clientinfo(), conninfo(), conf()) ->
     t().
 -callback open(clientinfo(), conninfo(), conf()) ->
     {_IsPresent :: true, t(), _ReplayContext} | false.
 -callback destroy(t() | clientinfo()) -> ok.
+-endif.
 
 %%--------------------------------------------------------------------
 %% Create a Session
diff --git a/apps/emqx_bridge_hstreamdb/test/emqx_bridge_hstreamdb_SUITE.erl b/apps/emqx_bridge_hstreamdb/test/emqx_bridge_hstreamdb_SUITE.erl
index a9232d5fe..4d165c03d 100644
--- a/apps/emqx_bridge_hstreamdb/test/emqx_bridge_hstreamdb_SUITE.erl
+++ b/apps/emqx_bridge_hstreamdb/test/emqx_bridge_hstreamdb_SUITE.erl
@@ -262,7 +262,6 @@ t_write_failure(Config) ->
     ProxyPort = ?config(proxy_port, Config),
     ProxyHost = ?config(proxy_host, Config),
     QueryMode = ?config(query_mode, Config),
-    EnableBatch = ?config(enable_batch, Config),
     Data = rand_data(),
     {{ok, _}, {ok, _}} =
         ?wait_async_action(
diff --git a/apps/emqx_dashboard/test/emqx_swagger_parameter_SUITE.erl b/apps/emqx_dashboard/test/emqx_swagger_parameter_SUITE.erl
index 14d6f48b7..9b32b0d98 100644
--- a/apps/emqx_dashboard/test/emqx_swagger_parameter_SUITE.erl
+++ b/apps/emqx_dashboard/test/emqx_swagger_parameter_SUITE.erl
@@ -19,7 +19,7 @@
 -behaviour(hocon_schema).
 
 %% API
--export([paths/0, api_spec/0, schema/1, fields/1]).
+-export([paths/0, api_spec/0, schema/1, namespace/0, fields/1]).
 -export([init_per_suite/1, end_per_suite/1]).
 -export([t_in_path/1, t_in_query/1, t_in_mix/1, t_without_in/1, t_ref/1, t_public_ref/1]).
 -export([t_require/1, t_query_enum/1, t_nullable/1, t_method/1, t_api_spec/1]).
@@ -562,6 +562,8 @@ schema("/method/ok") ->
 schema("/method/error") ->
     #{operationId => test, bar => #{200 => <<"ok">>}}.
 
+namespace() -> undefined.
+
 fields(page) ->
     [
         {per_page,
diff --git a/apps/emqx_dashboard/test/emqx_swagger_response_SUITE.erl b/apps/emqx_dashboard/test/emqx_swagger_response_SUITE.erl
index 5987ad8fa..85cc4b16b 100644
--- a/apps/emqx_dashboard/test/emqx_swagger_response_SUITE.erl
+++ b/apps/emqx_dashboard/test/emqx_swagger_response_SUITE.erl
@@ -680,6 +680,8 @@ to_schema(Object) ->
         post => #{responses => #{200 => Object, 201 => Object}}
     }.
 
+namespace() -> undefined.
+
 fields(good_ref) ->
     [
         {'webhook-host', mk(emqx_schema:ip_port(), #{default => <<"127.0.0.1:80">>})},
diff --git a/apps/emqx_durable_storage/test/props/emqx_ds_message_storage_bitmask_shim.erl b/apps/emqx_durable_storage/test/props/emqx_ds_message_storage_bitmask_shim.erl
index 9b5af9428..ddc199a44 100644
--- a/apps/emqx_durable_storage/test/props/emqx_ds_message_storage_bitmask_shim.erl
+++ b/apps/emqx_durable_storage/test/props/emqx_ds_message_storage_bitmask_shim.erl
@@ -11,9 +11,6 @@
 -export([store/2]).
 -export([iterate/2]).
 
--type topic() :: list(binary()).
--type time() :: integer().
-
 -opaque t() :: ets:tid().
 
 -export_type([t/0]).
diff --git a/apps/emqx_durable_storage/test/props/payload_gen.erl b/apps/emqx_durable_storage/test/props/payload_gen.erl
index 17e68f8d5..b969c0043 100644
--- a/apps/emqx_durable_storage/test/props/payload_gen.erl
+++ b/apps/emqx_durable_storage/test/props/payload_gen.erl
@@ -61,7 +61,7 @@
 }.
 
 %% For performance reasons we treat regular lists as streams, see `next/1'
--opaque cont(Data) ::
+-type cont(Data) ::
     fun(() -> stream(Data))
     | stream(Data).
 
@@ -78,11 +78,11 @@
     chunk_size :: non_neg_integer()
 }).
 
--opaque chunk_state() :: #chunk_state{}.
+-type chunk_state() :: #chunk_state{}.
 
 -record(interleave_state, {streams :: [{Tag :: term(), Stream :: term()}]}).
 
--opaque interleave_state() :: #interleave_state{}.
+-type interleave_state() :: #interleave_state{}.
 
 %% =============================================================================
 %% API functions
diff --git a/apps/emqx_telemetry/test/emqx_telemetry_SUITE.erl b/apps/emqx_telemetry/test/emqx_telemetry_SUITE.erl
index 396a7fb37..548a5b531 100644
--- a/apps/emqx_telemetry/test/emqx_telemetry_SUITE.erl
+++ b/apps/emqx_telemetry/test/emqx_telemetry_SUITE.erl
@@ -281,7 +281,7 @@ t_uuid_restored_from_file(Config) ->
     ),
     ok.
 
-t_uuid_saved_to_file(Config) ->
+t_uuid_saved_to_file(_Config) ->
     DataDir = emqx:data_dir(),
     NodeUUIDFile = filename:join(DataDir, "node.uuid"),
     ClusterUUIDFile = filename:join(DataDir, "cluster.uuid"),