diff --git a/src/ebusd/datahandler.cpp b/src/ebusd/datahandler.cpp
index 324105dc..864ee459 100755
--- a/src/ebusd/datahandler.cpp
+++ b/src/ebusd/datahandler.cpp
@@ -75,8 +75,11 @@ bool datahandler_register(UserInfo* userInfo, BusHandler* busHandler, MessageMap
   return success;
 }
 
-void DataSink::notifyUpdate(Message* message) {
+void DataSink::notifyUpdate(Message* message, bool changed) {
   if (message && message->hasLevel(m_levels)) {
+    if (m_changedOnly && !changed) {
+      return;
+    }
     m_updatedMessages[message->getKey()]++;
   }
 }
diff --git a/src/ebusd/datahandler.h b/src/ebusd/datahandler.h
index 8b5a0dce..9e93096e 100755
--- a/src/ebusd/datahandler.h
+++ b/src/ebusd/datahandler.h
@@ -143,8 +143,9 @@ class DataSink : virtual public DataHandler {
    * Constructor.
    * @param userInfo the @a UserInfo instance.
    * @param user the user name for determining the allowed access levels (fall back to default levels).
+   * @param changedOnly whether to handle changed messages only in the updates.
    */
-  DataSink(const UserInfo* userInfo, const string& user) {
+  DataSink(const UserInfo* userInfo, const string& user, bool changedOnly) : m_changedOnly(changedOnly) {
     m_levels = userInfo->getLevels(userInfo->hasUser(user) ? user : "");
   }
 
@@ -159,8 +160,9 @@ class DataSink : virtual public DataHandler {
   /**
    * Notify the sink of an updated @a Message (not necessarily changed though).
    * @param message the updated @a Message.
+   * @param changed whether the message data changed since the last notification.
    */
-  virtual void notifyUpdate(Message* message);
+  virtual void notifyUpdate(Message* message, bool changed);
 
   /**
    * Notify the sink of the latest update check result.
@@ -178,6 +180,9 @@ class DataSink : virtual public DataHandler {
   /** the allowed access levels. */
   string m_levels;
 
+  /** whether to handle changed messages only in the updates. */
+  bool m_changedOnly;
+
   /** a map of updated @p Message keys. */
   map<uint64_t, int> m_updatedMessages;
 };
diff --git a/src/ebusd/knxhandler.cpp b/src/ebusd/knxhandler.cpp
index da2690e1..2bca8694 100644
--- a/src/ebusd/knxhandler.cpp
+++ b/src/ebusd/knxhandler.cpp
@@ -163,7 +163,7 @@ bool knxhandler_register(UserInfo* userInfo, BusHandler* busHandler, MessageMap*
 }
 
 KnxHandler::KnxHandler(UserInfo* userInfo, BusHandler* busHandler, MessageMap* messages)
-  : DataSink(userInfo, "knx"), DataSource(busHandler), WaitThread(), m_messages(messages),
+  : DataSink(userInfo, "knx", true), DataSource(busHandler), WaitThread(), m_messages(messages),
     m_start(0), m_lastUpdateCheckResult("."),
     m_lastScanStatus(SCAN_STATUS_NONE), m_scanFinishReceived(false), m_lastErrorLogTime(0) {
   m_con = KnxConnection::create(g_url);
@@ -709,7 +709,7 @@ void KnxHandler::handleGroupTelegram(knx_addr_t src, knx_addr_t dest, int len, c
 #define UPTIME_INTERVAL 3600
 
 void KnxHandler::run() {
-  time_t lastTaskRun, now, lastSignal = 0, lastUptime = 0, lastUpdates = 0;
+  time_t lastTaskRun, now, lastSignal = 0, lastUptime = 0;
   bool signal = false;
   result_t result = RESULT_OK;
   time(&now);
@@ -899,7 +899,6 @@ void KnxHandler::run() {
     if (!m_updatedMessages.empty()) {
       m_messages->lock();
       if (m_con->isConnected()) {
-        time_t maxUpdates = 0;
         for (auto it = m_updatedMessages.begin(); it != m_updatedMessages.end(); ) {
           const vector<Message*>* messages = m_messages->getByKey(it->first);
           if (!messages) {
@@ -911,18 +910,10 @@ void KnxHandler::run() {
             if (changeTime <= 0) {
               continue;
             }
-            if (changeTime > lastUpdates && changeTime > maxUpdates) {
-              maxUpdates = changeTime;
-            }
             const auto mit = m_subscribedMessages.find(message->getKey());
             if (mit == m_subscribedMessages.cend()) {
               continue;
             }
-            if (!(message->getDataHandlerState()&2)) {
-              message->setDataHandlerState(2, true);  // first update still needed
-            } else if (changeTime <= lastUpdates) {
-              continue;
-            }
             for (auto destFlags : mit->second) {
               auto sit = m_subscribedGroups.find(destFlags);
               if (sit == m_subscribedGroups.end()) {
@@ -941,7 +932,6 @@ void KnxHandler::run() {
           }
           it = m_updatedMessages.erase(it);
         }
-        lastUpdates = maxUpdates == 0 || lastUpdates > maxUpdates ? now : maxUpdates + 1;
       } else {
         m_updatedMessages.clear();
       }
diff --git a/src/ebusd/mainloop.cpp b/src/ebusd/mainloop.cpp
index 32383250..66f2bd6e 100644
--- a/src/ebusd/mainloop.cpp
+++ b/src/ebusd/mainloop.cpp
@@ -352,8 +352,9 @@ void MainLoop::run() {
       m_messages->lock();
       m_messages->findAll("", "", "*", false, true, true, true, true, true, sinkSince, now, false, &messages);
       for (const auto message : messages) {
+        bool changed = message->getLastChangeTime() >= sinkSince;
         for (const auto dataSink : dataSinks) {
-          dataSink->notifyUpdate(message);
+          dataSink->notifyUpdate(message, changed);
         }
       }
       m_messages->unlock();
diff --git a/src/ebusd/mqtthandler.cpp b/src/ebusd/mqtthandler.cpp
index 6e1f17c1..b3204655 100755
--- a/src/ebusd/mqtthandler.cpp
+++ b/src/ebusd/mqtthandler.cpp
@@ -368,7 +368,8 @@ string removeTrailingNonTopicPart(const string& str) {
 }
 
 MqttHandler::MqttHandler(UserInfo* userInfo, BusHandler* busHandler, MessageMap* messages)
-  : DataSink(userInfo, "mqtt"), DataSource(busHandler), WaitThread(), m_messages(messages), m_connected(false),
+  : DataSink(userInfo, "mqtt", g_onlyChanges), DataSource(busHandler), WaitThread(),
+    m_messages(messages), m_connected(false),
     m_lastUpdateCheckResult("."), m_lastScanStatus(SCAN_STATUS_NONE) {
   m_definitionsSince = 0;
   m_client = nullptr;
@@ -696,7 +697,7 @@ void splitFields(const string& str, vector<string>* row) {
 }
 
 void MqttHandler::run() {
-  time_t lastTaskRun, now, start, lastSignal = 0, lastUpdates = 0;
+  time_t lastTaskRun, now, start, lastSignal = 0;
   bool signal = false;
   bool globalHasName = m_globalTopic.has("name");
   string signalTopic = m_globalTopic.get("", "signal");
@@ -1068,27 +1069,21 @@ void MqttHandler::run() {
     if (!m_updatedMessages.empty()) {
       m_messages->lock();
       if (m_connected) {
-        time_t maxUpdates = 0;
         for (auto it = m_updatedMessages.begin(); it != m_updatedMessages.end(); ) {
           const vector<Message*>* messages = m_messages->getByKey(it->first);
           if (messages) {
             for (const auto& message : *messages) {
               time_t changeTime = message->getLastChangeTime();
-              if (changeTime > 0 && message->isAvailable()
-              && (!g_onlyChanges || changeTime > lastUpdates)) {
+              if (changeTime > 0 && message->isAvailable()) {
                 updates.str("");
                 updates.clear();
                 updates << dec;
                 publishMessage(message, &updates);
               }
-              if (changeTime > lastUpdates && changeTime > maxUpdates) {
-                maxUpdates = changeTime;
-              }
             }
           }
           it = m_updatedMessages.erase(it);
         }
-        lastUpdates = maxUpdates == 0 || lastUpdates > maxUpdates ? now : maxUpdates + 1;
       } else {
         m_updatedMessages.clear();
       }