diff --git a/libs/main/mqtt_client/pimqttclient.h b/libs/main/mqtt_client/pimqttclient.h
index edd0fbe5..1e12c47d 100644
--- a/libs/main/mqtt_client/pimqttclient.h
+++ b/libs/main/mqtt_client/pimqttclient.h
@@ -28,8 +28,6 @@
 #include "piliterals_time.h"
 #include "pimqtttypes.h"
 #include "pip_mqtt_client_export.h"
-#include "piprotectedvariable.h"
-#include "pithread.h"
 #include "pithreadpoolworker.h"
 
 
@@ -52,6 +50,7 @@ public:
 	void unsubscribe(const PIString & topic);
 
 	void publish(const PIString & topic, const PIByteArray & msg, QoS qos = QoS::Level0);
+	void publish(const MessageConst & msg);
 	void unsubscribeAll() { unsubscribe("#"); }
 
 	bool isConnecting() const { return m_status == Connecting; }
@@ -59,7 +58,7 @@ public:
 
 	EVENT0(connected);
 	EVENT1(disconnected, PIMQTT::Error, code);
-	EVENT1(received, PIMQTT::Message, message);
+	EVENT1(received, PIMQTT::MessageConst, message);
 
 private:
 	NO_COPY_CLASS(Client)
@@ -85,11 +84,11 @@ private:
 
 	void mqtt_connectionLost();
 	void mqtt_deliveryComplete(int token);
-	void mqtt_messageArrived(const Message & msg);
+	void mqtt_messageArrived(const MessageConst & msg);
 
 	void connectInternal(const ConnectInfo & ci);
 	void disconnectInternal();
-	void publishInternal(const Message & m);
+	void publishInternal(const MessageConst & m);
 	void subscribeInternal(const Subscribe & sub);
 	void unsubscribeInternal(const PIString & topic);
 	void destroy();
diff --git a/libs/main/mqtt_common/pimqtttypes.cpp b/libs/main/mqtt_common/pimqtttypes.cpp
new file mode 100644
index 00000000..9df77997
--- /dev/null
+++ b/libs/main/mqtt_common/pimqtttypes.cpp
@@ -0,0 +1,31 @@
+#include "pimqtttypes.h"
+
+
+PIMQTT::MessageMutable & PIMQTT::MessageMutable::setTopic(PIString t) {
+	m_topic = t;
+	return *this;
+}
+
+
+PIMQTT::MessageMutable & PIMQTT::MessageMutable::setBody(PIByteArray b) {
+	m_payload = b;
+	return *this;
+}
+
+
+PIMQTT::MessageMutable & PIMQTT::MessageMutable::setDuplicate(bool yes) {
+	m_is_duplicate = yes;
+	return *this;
+}
+
+
+PIMQTT::MessageMutable & PIMQTT::MessageMutable::setQos(QoS qos) {
+	m_qos = qos;
+	return *this;
+}
+
+
+PIMQTT::MessageMutable & PIMQTT::MessageMutable::setID(int id) {
+	m_msg_id = id;
+	return *this;
+}
diff --git a/libs/main/mqtt_common/pimqtttypes.h b/libs/main/mqtt_common/pimqtttypes.h
index 641aff25..17c90361 100644
--- a/libs/main/mqtt_common/pimqtttypes.h
+++ b/libs/main/mqtt_common/pimqtttypes.h
@@ -26,7 +26,7 @@
 #define pimqtttypes_h
 
 #include "pip_export.h"
-#include "pistring.h"
+#include "pistringlist.h"
 
 
 //! \~english Namespace with shared MQTT data types.
@@ -51,14 +51,113 @@ enum class Error {
 	NotAuthorized               = 5 /** */,
 };
 
-struct PIP_EXPORT Message {
-	bool isValid() const { return topic.isNotEmpty(); }
-	PIString topic;
-	PIByteArray payload;
-	PIMap<int, PIString> properties; // for v5
-	QoS qos           = QoS::Level0;
-	int msg_id        = 0;
-	bool is_duplicate = false;
+
+//! \~\ingroup MQTT
+//! \~\brief
+//! \~english Immutable MQTT message.
+//! \~russian Неизменяемое MQTT-сообщение.
+class PIP_EXPORT MessageConst {
+public:
+	//! \~english Returns if the topic is not empty.
+	//! \~russian Возвращает не пустой ли топик.
+	bool isValid() const { return m_topic.isNotEmpty(); }
+
+	//! \~english Returns the topic.
+	//! \~russian Возвращает топик.
+	const PIString & topic() const { return m_topic; }
+
+	//! \~english Returns the topic split into non-empty components.
+	//! \~russian Возвращает топик, разбитый на непустые компоненты.
+	PIStringList topicList() const { return m_topic.split('/').removeAll({}); }
+
+	//! \~english Returns the message body.
+	//! \~russian Возвращает тело сообщения.
+	const PIByteArray & body() const { return m_payload; }
+
+	//! \~english Returns the message body.
+	//! \~russian Возвращает тело сообщения.
+	const PIByteArray & payload() const { return m_payload; }
+
+	//! \~english Returns extracted path arguments.
+	//! \~russian Возвращает извлеченные аргументы пути.
+	const PIMap<PIString, PIString> & pathArguments() const { return m_path_arguments; }
+
+	//! \~english Returns map of properties.
+	//! \~russian Возвращает карту свойств.
+	const PIMap<int, PIString> & properties() const { return m_properties; }
+
+
+	//! \~english Returns \c true for .
+	//! \~russian Возвращает \c true для .
+	bool isDuplicate() const { return m_is_duplicate; }
+
+	//! \~english Returns QoS.
+	//! \~russian Возвращает QoS.
+	QoS qos() const { return m_qos; }
+
+	//! \~english Returns message ID.
+	//! \~russian Возвращает ID сообщения.
+	int ID() const { return m_msg_id; }
+
+protected:
+	PIString m_topic;
+	PIMap<PIString, PIString> m_path_arguments;
+	PIByteArray m_payload;
+	PIMap<int, PIString> m_properties; // for v5
+	QoS m_qos           = QoS::Level0;
+	int m_msg_id        = 0;
+	bool m_is_duplicate = false;
+};
+
+
+//! \~\ingroup MQTT
+//! \~\brief
+//! \~english Mutable MQTT message.
+//! \~russian Изменяемое MQTT-сообщение.
+class PIP_EXPORT MessageMutable: public MessageConst {
+public:
+	//! \~english Sets the topic.
+	//! \~russian Устанавливает топик.
+	MessageMutable & setTopic(PIString t);
+
+	//! \~english Sets the message body.
+	//! \~russian Устанавливает тело сообщения.
+	MessageMutable & setBody(PIByteArray b);
+
+	//! \~english Sets the message body.
+	//! \~russian Устанавливает тело сообщения.
+	MessageMutable & setPayload(PIByteArray b) { return setBody(b); }
+
+
+	//! \~english Returns path arguments.
+	//! \~russian Возвращает аргументы пути.
+	const PIMap<PIString, PIString> & pathArguments() const { return m_path_arguments; }
+
+	//! \~english Returns a modifiable map of path arguments.
+	//! \~russian Возвращает изменяемую карту аргументов пути.
+	PIMap<PIString, PIString> & pathArguments() { return m_path_arguments; }
+
+
+	//! \~english Returns map of properties.
+	//! \~russian Возвращает карту свойств.
+	const PIMap<int, PIString> & properties() const { return m_properties; }
+
+	//! \~english Returns a modifiable map of properties.
+	//! \~russian Возвращает изменяемую карту свойств.
+	PIMap<int, PIString> & properties() { return m_properties; }
+
+
+	//! \~english Returns \c true for .
+	//! \~russian Возвращает \c true для .
+	MessageMutable & setDuplicate(bool yes);
+
+	//! \~english Returns QoS.
+	//! \~russian Возвращает QoS.
+	MessageMutable & setQos(QoS qos);
+
+	//! \~english Returns message ID.
+	//! \~russian Возвращает ID сообщения.
+	MessageMutable & setID(int id);
 };
 
 
diff --git a/libs/mqtt_client/pimqttclient.cpp b/libs/mqtt_client/pimqttclient.cpp
index d23ad227..6518d7b2 100644
--- a/libs/mqtt_client/pimqttclient.cpp
+++ b/libs/mqtt_client/pimqttclient.cpp
@@ -41,12 +41,12 @@ PRIVATE_DEFINITION_START(PIMQTT::Client)
 	}
 
 	static int messageArrived_callback(void * context, char * topicName, int topicLen, MQTTClient_message * message) {
-		PIMQTT::Message msg;
-		msg.topic        = PIString::fromUTF8(topicName);
-		msg.payload      = PIByteArray(message->payload, message->payloadlen);
-		msg.msg_id       = message->msgid;
-		msg.is_duplicate = message->dup != 0;
-		msg.qos          = static_cast<PIMQTT::QoS>(message->qos);
+		PIMQTT::MessageMutable msg;
+		msg.setTopic(PIString::fromUTF8(topicName));
+		msg.setPayload(PIByteArray(message->payload, message->payloadlen));
+		msg.setID(message->msgid);
+		msg.setDuplicate(message->dup != 0);
+		msg.setQos(static_cast<PIMQTT::QoS>(message->qos));
 		MQTTClient_freeMessage(&message);
 		MQTTClient_free(topicName);
 		((PIMQTT::Client *)context)->mqtt_messageArrived(msg);
@@ -101,12 +101,17 @@ void PIMQTT::Client::unsubscribe(const PIString & topic) {
 
 
 void PIMQTT::Client::publish(const PIString & topic, const PIByteArray & msg, QoS qos) {
+	MessageMutable m;
+	m.setTopic(topic);
+	m.setPayload(msg);
+	m.setQos(qos);
+	publish(m);
+}
+
+
+void PIMQTT::Client::publish(const MessageConst & msg) {
 	if (is_destoying) return;
-	Message m;
-	m.topic   = topic;
-	m.payload = msg;
-	m.qos     = qos;
-	worker->enqueueTask([this, m] { publishInternal(m); });
+	worker->enqueueTask([this, msg] { publishInternal(msg); });
 }
 
 
@@ -121,7 +126,7 @@ void PIMQTT::Client::mqtt_connectionLost() {
 void PIMQTT::Client::mqtt_deliveryComplete(int token) {}
 
 
-void PIMQTT::Client::mqtt_messageArrived(const Message & msg) {
+void PIMQTT::Client::mqtt_messageArrived(const MessageConst & msg) {
 	piCoutObj << "mqtt_messageArrived";
 	received(msg);
 }
@@ -169,13 +174,13 @@ inline void PIMQTT::Client::disconnectInternal() {
 }
 
 
-void PIMQTT::Client::publishInternal(const Message & m) {
+void PIMQTT::Client::publishInternal(const MessageConst & m) {
 	if (!PRIVATE->client) return;
 	MQTTClient_message pubmsg = MQTTClient_message_initializer;
-	pubmsg.payload            = const_cast<void *>(static_cast<const void *>(m.payload.data()));
-	pubmsg.payloadlen         = m.payload.size_s();
-	pubmsg.qos                = static_cast<int>(m.qos);
-	int ret                   = MQTTClient_publishMessage(PRIVATE->client, m.topic.dataAscii(), &pubmsg, nullptr);
+	pubmsg.payload            = const_cast<void *>(static_cast<const void *>(m.payload().data()));
+	pubmsg.payloadlen         = m.payload().size_s();
+	pubmsg.qos                = static_cast<int>(m.qos());
+	int ret                   = MQTTClient_publishMessage(PRIVATE->client, m.topic().dataAscii(), &pubmsg, nullptr);
 	if (ret != MQTTCLIENT_SUCCESS) {
 		piCoutObj << "Failed to publishMessage, code" << ret;
 	}
diff --git a/main.cpp b/main.cpp
index 2c3aeb8c..fa83d4df 100644
--- a/main.cpp
+++ b/main.cpp
@@ -35,7 +35,9 @@ int main(int argc, char * argv[]) {
 		piCout << "disconnected code" << (int)code;
 		cl.connect("localhost", "PIP");
 	});
-	CONNECTL(&cl, received, [](const PIMQTT::Message & message) { piCout << "received" << message.topic << message.payload.size(); });
+	CONNECTL(&cl, received, [](const PIMQTT::MessageConst & message) {
+		piCout << "received" << message.topic() << message.payload().size();
+	});
 
 	cl.connect("localhost", "PIP");