diff --git a/include/zenoh-pico/protocol/codec/network.h b/include/zenoh-pico/protocol/codec/network.h
index 9569cc36f..661ee9de2 100644
--- a/include/zenoh-pico/protocol/codec/network.h
+++ b/include/zenoh-pico/protocol/codec/network.h
@@ -24,20 +24,20 @@
 extern "C" {
 #endif
 
-z_result_t _z_push_encode(_z_wbuf_t *wbf, const _z_n_msg_push_t *msg, bool *is_express);
+z_result_t _z_push_encode(_z_wbuf_t *wbf, const _z_n_msg_push_t *msg);
 z_result_t _z_push_decode(_z_n_msg_push_t *msg, _z_zbuf_t *zbf, uint8_t header, _z_arc_slice_t *arcs);
-z_result_t _z_request_encode(_z_wbuf_t *wbf, const _z_n_msg_request_t *msg, bool *is_express);
+z_result_t _z_request_encode(_z_wbuf_t *wbf, const _z_n_msg_request_t *msg);
 z_result_t _z_request_decode(_z_n_msg_request_t *msg, _z_zbuf_t *zbf, uint8_t header, _z_arc_slice_t *arcs);
-z_result_t _z_response_encode(_z_wbuf_t *wbf, const _z_n_msg_response_t *msg, bool *is_express);
+z_result_t _z_response_encode(_z_wbuf_t *wbf, const _z_n_msg_response_t *msg);
 z_result_t _z_response_decode(_z_n_msg_response_t *msg, _z_zbuf_t *zbf, uint8_t header, _z_arc_slice_t *arcs);
 z_result_t _z_response_final_encode(_z_wbuf_t *wbf, const _z_n_msg_response_final_t *msg);
 z_result_t _z_response_final_decode(_z_n_msg_response_final_t *msg, _z_zbuf_t *zbf, uint8_t header);
-z_result_t _z_declare_encode(_z_wbuf_t *wbf, const _z_n_msg_declare_t *decl, bool *is_express);
+z_result_t _z_declare_encode(_z_wbuf_t *wbf, const _z_n_msg_declare_t *decl);
 z_result_t _z_declare_decode(_z_n_msg_declare_t *decl, _z_zbuf_t *zbf, uint8_t header);
 z_result_t _z_n_interest_encode(_z_wbuf_t *wbf, const _z_n_msg_interest_t *interest);
 z_result_t _z_n_interest_decode(_z_n_msg_interest_t *interest, _z_zbuf_t *zbf, uint8_t header);
 
-z_result_t _z_network_message_encode(_z_wbuf_t *wbf, const _z_network_message_t *msg, bool *is_express);
+z_result_t _z_network_message_encode(_z_wbuf_t *wbf, const _z_network_message_t *msg);
 z_result_t _z_network_message_decode(_z_network_message_t *msg, _z_zbuf_t *zbf, _z_arc_slice_t *arcs);
 
 #ifdef __cplusplus
diff --git a/include/zenoh-pico/protocol/definitions/network.h b/include/zenoh-pico/protocol/definitions/network.h
index 2bc7eb0ba..2af9d97ef 100644
--- a/include/zenoh-pico/protocol/definitions/network.h
+++ b/include/zenoh-pico/protocol/definitions/network.h
@@ -80,8 +80,6 @@ extern "C" {
 
 typedef _z_qos_t _z_n_qos_t;
 
-#define _Z_N_QOS_IS_EXPRESS_FLAG (1 << 4)
-
 static inline _z_qos_t _z_n_qos_create(bool express, z_congestion_control_t congestion_control, z_priority_t priority) {
     _z_n_qos_t ret;
     bool nodrop = congestion_control == Z_CONGESTION_CONTROL_DROP ? 0 : 1;
diff --git a/src/protocol/codec/network.c b/src/protocol/codec/network.c
index 93d829449..44cf9cde9 100644
--- a/src/protocol/codec/network.c
+++ b/src/protocol/codec/network.c
@@ -38,14 +38,11 @@
 
 /*------------------ Push Message ------------------*/
 
-z_result_t _z_push_encode(_z_wbuf_t *wbf, const _z_n_msg_push_t *msg, bool *is_express) {
+z_result_t _z_push_encode(_z_wbuf_t *wbf, const _z_n_msg_push_t *msg) {
     uint8_t header = _Z_MID_N_PUSH | (_z_keyexpr_is_local(&msg->_key) ? _Z_FLAG_N_REQUEST_M : 0);
     bool has_suffix = _z_keyexpr_has_suffix(&msg->_key);
     bool has_qos_ext = msg->_qos._val != _Z_N_QOS_DEFAULT._val;
     bool has_timestamp_ext = _z_timestamp_check(&msg->_timestamp);
-    if (is_express != NULL) {
-        *is_express = _Z_HAS_FLAG(msg->_qos._val, _Z_N_QOS_IS_EXPRESS_FLAG);
-    }
     if (has_suffix) {
         header |= _Z_FLAG_N_REQUEST_N;
     }
@@ -114,7 +111,7 @@ z_result_t _z_push_decode(_z_n_msg_push_t *msg, _z_zbuf_t *zbf, uint8_t header,
 }
 
 /*------------------ Request Message ------------------*/
-z_result_t _z_request_encode(_z_wbuf_t *wbf, const _z_n_msg_request_t *msg, bool *is_express) {
+z_result_t _z_request_encode(_z_wbuf_t *wbf, const _z_n_msg_request_t *msg) {
     z_result_t ret = _Z_RES_OK;
     uint8_t header = _Z_MID_N_REQUEST | (_z_keyexpr_is_local(&msg->_key) ? _Z_FLAG_N_REQUEST_M : 0);
     bool has_suffix = _z_keyexpr_has_suffix(&msg->_key);
@@ -131,9 +128,6 @@ z_result_t _z_request_encode(_z_wbuf_t *wbf, const _z_n_msg_request_t *msg, bool
         uint8_t extheader = 0x01 | _Z_MSG_EXT_ENC_ZINT | (exts.n ? _Z_FLAG_Z_Z : 0);
         _Z_RETURN_IF_ERR(_z_uint8_encode(wbf, extheader));
         _Z_RETURN_IF_ERR(_z_zsize_encode(wbf, msg->_ext_qos._val));
-        if (is_express != NULL) {
-            *is_express = _Z_HAS_FLAG(msg->_ext_qos._val, _Z_N_QOS_IS_EXPRESS_FLAG);
-        }
     }
     if (exts.ext_tstamp) {
         exts.n -= 1;
@@ -244,7 +238,7 @@ z_result_t _z_request_decode(_z_n_msg_request_t *msg, _z_zbuf_t *zbf, const uint
 }
 
 /*------------------ Response Message ------------------*/
-z_result_t _z_response_encode(_z_wbuf_t *wbf, const _z_n_msg_response_t *msg, bool *is_express) {
+z_result_t _z_response_encode(_z_wbuf_t *wbf, const _z_n_msg_response_t *msg) {
     z_result_t ret = _Z_RES_OK;
     uint8_t header = _Z_MID_N_RESPONSE;
     _Z_DEBUG("Encoding _Z_MID_N_RESPONSE");
@@ -253,9 +247,6 @@ z_result_t _z_response_encode(_z_wbuf_t *wbf, const _z_n_msg_response_t *msg, bo
     bool has_responder_ext = _z_id_check(msg->_ext_responder._zid) || msg->_ext_responder._eid != 0;
     int n_ext = (has_qos_ext ? 1 : 0) + (has_ts_ext ? 1 : 0) + (has_responder_ext ? 1 : 0);
     bool has_suffix = _z_keyexpr_has_suffix(&msg->_key);
-    if (is_express != NULL) {
-        *is_express = _Z_HAS_FLAG(msg->_ext_qos._val, _Z_N_QOS_IS_EXPRESS_FLAG);
-    }
     if (_z_keyexpr_is_local(&msg->_key)) {
         _Z_SET_FLAG(header, _Z_FLAG_N_RESPONSE_M);
     }
@@ -398,13 +389,10 @@ z_result_t _z_response_final_decode(_z_n_msg_response_final_t *msg, _z_zbuf_t *z
     return ret;
 }
 
-z_result_t _z_declare_encode(_z_wbuf_t *wbf, const _z_n_msg_declare_t *decl, bool *is_express) {
+z_result_t _z_declare_encode(_z_wbuf_t *wbf, const _z_n_msg_declare_t *decl) {
     uint8_t header = _Z_MID_N_DECLARE;
     bool has_qos_ext = decl->_ext_qos._val != _Z_N_QOS_DEFAULT._val;
     bool has_timestamp_ext = _z_timestamp_check(&decl->_ext_timestamp);
-    if (is_express != NULL) {
-        *is_express = _Z_HAS_FLAG(decl->_ext_qos._val, _Z_N_QOS_IS_EXPRESS_FLAG);
-    }
     int n_ext = (has_qos_ext ? 1 : 0) + (has_timestamp_ext ? 1 : 0);
     if (n_ext != 0) {
         header |= _Z_FLAG_N_Z;
@@ -501,19 +489,19 @@ z_result_t _z_n_interest_decode(_z_n_msg_interest_t *interest, _z_zbuf_t *zbf, u
     return _z_interest_decode(&interest->_interest, zbf, is_final, has_ext);
 }
 
-z_result_t _z_network_message_encode(_z_wbuf_t *wbf, const _z_network_message_t *msg, bool *is_express) {
+z_result_t _z_network_message_encode(_z_wbuf_t *wbf, const _z_network_message_t *msg) {
     switch (msg->_tag) {
         case _Z_N_DECLARE: {
-            return _z_declare_encode(wbf, &msg->_body._declare, is_express);
+            return _z_declare_encode(wbf, &msg->_body._declare);
         } break;
         case _Z_N_PUSH: {
-            return _z_push_encode(wbf, &msg->_body._push, is_express);
+            return _z_push_encode(wbf, &msg->_body._push);
         } break;
         case _Z_N_REQUEST: {
-            return _z_request_encode(wbf, &msg->_body._request, is_express);
+            return _z_request_encode(wbf, &msg->_body._request);
         } break;
         case _Z_N_RESPONSE: {
-            return _z_response_encode(wbf, &msg->_body._response, is_express);
+            return _z_response_encode(wbf, &msg->_body._response);
         } break;
         case _Z_N_RESPONSE_FINAL: {
             return _z_response_final_encode(wbf, &msg->_body._response_final);
diff --git a/src/protocol/codec/transport.c b/src/protocol/codec/transport.c
index 3bc17d24b..894fb41d8 100644
--- a/src/protocol/codec/transport.c
+++ b/src/protocol/codec/transport.c
@@ -388,7 +388,7 @@ z_result_t _z_frame_encode(_z_wbuf_t *wbf, uint8_t header, const _z_t_msg_frame_
     if (ret == _Z_RES_OK) {
         size_t len = _z_network_message_svec_len(&msg->_messages);
         for (size_t i = 0; i < len; i++) {
-            _Z_RETURN_IF_ERR(_z_network_message_encode(wbf, _z_network_message_svec_get(&msg->_messages, i), NULL))
+            _Z_RETURN_IF_ERR(_z_network_message_encode(wbf, _z_network_message_svec_get(&msg->_messages, i)))
         }
     }
 
diff --git a/src/transport/raweth/tx.c b/src/transport/raweth/tx.c
index 9116930c5..e8f9be4c4 100644
--- a/src/transport/raweth/tx.c
+++ b/src/transport/raweth/tx.c
@@ -252,7 +252,7 @@ z_result_t _z_raweth_send_n_msg(_z_session_t *zn, const _z_network_message_t *n_
     _Z_CLEAN_RETURN_IF_ERR(_z_transport_message_encode(&ztm->_common._wbuf, &t_msg),
                            _z_transport_tx_mutex_unlock(&ztm->_common));
     // Encode the network message
-    if (_z_network_message_encode(&ztm->_common._wbuf, n_msg, NULL) == _Z_RES_OK) {
+    if (_z_network_message_encode(&ztm->_common._wbuf, n_msg) == _Z_RES_OK) {
         // Write the eth header
         _Z_CLEAN_RETURN_IF_ERR(__unsafe_z_raweth_write_header(&ztm->_common._link, &ztm->_common._wbuf),
                                _z_transport_tx_mutex_unlock(&ztm->_common));
@@ -266,8 +266,7 @@ z_result_t _z_raweth_send_n_msg(_z_session_t *zn, const _z_network_message_t *n_
         // Create an expandable wbuf for fragmentation
         _z_wbuf_t fbf = _z_wbuf_make(_Z_FRAG_BUFF_BASE_SIZE, true);
         // Encode the message on the expandable wbuf
-        _Z_CLEAN_RETURN_IF_ERR(_z_network_message_encode(&fbf, n_msg, NULL),
-                               _z_transport_tx_mutex_unlock(&ztm->_common));
+        _Z_CLEAN_RETURN_IF_ERR(_z_network_message_encode(&fbf, n_msg), _z_transport_tx_mutex_unlock(&ztm->_common));
         // Fragment and send the message
         bool is_first = true;
         while (_z_wbuf_len(&fbf) > 0) {
diff --git a/tests/z_msgcodec_test.c b/tests/z_msgcodec_test.c
index b1c288a2f..a87c258e4 100644
--- a/tests/z_msgcodec_test.c
+++ b/tests/z_msgcodec_test.c
@@ -1163,7 +1163,7 @@ void declare_message(void) {
     _z_network_message_t n_msg = gen_declare_message();
 
     // Encode
-    z_result_t res = _z_network_message_encode(&wbf, &n_msg, NULL);
+    z_result_t res = _z_network_message_encode(&wbf, &n_msg);
     assert(res == _Z_RES_OK);
     (void)(res);
 
@@ -1433,7 +1433,7 @@ void push_message(void) {
     printf("\n>> Push message\n");
     _z_wbuf_t wbf = gen_wbuf(UINT16_MAX);
     _z_n_msg_push_t expected = gen_push();
-    assert(_z_push_encode(&wbf, &expected, NULL) == _Z_RES_OK);
+    assert(_z_push_encode(&wbf, &expected) == _Z_RES_OK);
     _z_n_msg_push_t decoded = {0};
     _z_arc_slice_t arcs = {0};
     _z_zbuf_t zbf = _z_wbuf_to_zbuf(&wbf);
@@ -1505,7 +1505,7 @@ void request_message(void) {
     printf("\n>> Request message\n");
     _z_wbuf_t wbf = gen_wbuf(UINT16_MAX);
     _z_n_msg_request_t expected = gen_request();
-    assert(_z_request_encode(&wbf, &expected, NULL) == _Z_RES_OK);
+    assert(_z_request_encode(&wbf, &expected) == _Z_RES_OK);
     _z_n_msg_request_t decoded = {0};
     _z_arc_slice_t arcs = {0};
     _z_zbuf_t zbf = _z_wbuf_to_zbuf(&wbf);
@@ -1564,7 +1564,7 @@ void response_message(void) {
     printf("\n>> Response message\n");
     _z_wbuf_t wbf = gen_wbuf(UINT16_MAX);
     _z_n_msg_response_t expected = gen_response();
-    assert(_z_response_encode(&wbf, &expected, NULL) == _Z_RES_OK);
+    assert(_z_response_encode(&wbf, &expected) == _Z_RES_OK);
     _z_n_msg_response_t decoded = {0};
     _z_arc_slice_t arcs = {0};
     _z_zbuf_t zbf = _z_wbuf_to_zbuf(&wbf);