diff --git a/src/ebusd/knxhandler.cpp b/src/ebusd/knxhandler.cpp
index 8d257408..4a912a56 100644
--- a/src/ebusd/knxhandler.cpp
+++ b/src/ebusd/knxhandler.cpp
@@ -760,7 +760,7 @@ void KnxHandler::run() {
       }
       if (m_con->isConnected()) {
         deque<Message*> messages;
-        m_messages->findAll("", "", m_levels, false, true, true, true, true, true, 0, 0, true, &messages);
+        m_messages->findAll("", "", m_levels, false, true, true, true, true, true, 0, 0, false, &messages);
         int addCnt = 0;
         for (const auto& message : messages) {
           const auto mit = m_subscribedMessages.find(message->getKey());
@@ -770,10 +770,12 @@ void KnxHandler::run() {
           if (message->getDstAddress() == SYN) {
             continue;  // not usable in absence of destination address
           }
-          bool isWrite = message->isWrite() && !message->isPassive();  // from KNX perspective
-          if (message->getCreateTime() <= definitionsSince) {  // only newer defined
+          if (message->getCreateTime() <= definitionsSince  // only newer defined
+          && (!message->isConditional() || message->getAvailableSinceTime() <= definitionsSince)) {  // unless conditional
             continue;
           }
+          logOtherDebug("knx", "checking association to %s %s", message->getCircuit().c_str(), message->getName().c_str());
+          bool isWrite = message->isWrite() && !message->isPassive();  // from KNX perspective
           ssize_t fieldCount = static_cast<signed>(message->getFieldCount());
           if (isWrite && fieldCount > 1) {
             // impossible with more than one field
diff --git a/src/ebusd/mqtthandler.cpp b/src/ebusd/mqtthandler.cpp
index c734cc5c..20ec1f79 100755
--- a/src/ebusd/mqtthandler.cpp
+++ b/src/ebusd/mqtthandler.cpp
@@ -816,7 +816,8 @@ void MqttHandler::run() {
               }
             }
             message->setDataHandlerState(1, true);
-          } else if (message->getCreateTime() <= m_definitionsSince) {  // only newer defined
+          } else if (message->getCreateTime() <= m_definitionsSince  // only newer defined
+          && (!message->isConditional() || message->getAvailableSinceTime() <= m_definitionsSince)) {  // unless conditional
             continue;
           }
           if (!FileReader::matches(message->getCircuit(), filterCircuit, true, true)
diff --git a/src/lib/ebus/message.cpp b/src/lib/ebus/message.cpp
index 75b2770f..f7faa051 100644
--- a/src/lib/ebus/message.cpp
+++ b/src/lib/ebus/message.cpp
@@ -109,7 +109,7 @@ Message::Message(const string& filename, const string& circuit, const string& le
       m_id(id), m_key(createKey(id, isWrite, isPassive, srcAddress, dstAddress)),
       m_data(data), m_deleteData(deleteData),
       m_pollPriority(pollPriority),
-      m_usedByCondition(false), m_isScanMessage(false), m_condition(condition),
+      m_usedByCondition(false), m_isScanMessage(false), m_condition(condition), m_availableSinceTime(0),
       m_dataHandlerState(0), m_lastUpdateTime(0), m_lastChangeTime(0), m_pollOrder(0), m_lastPollTime(0) {
   if (circuit == "scan") {
     setScanMessage();
@@ -129,7 +129,7 @@ Message::Message(const string& circuit, const string& level, const string& name,
       m_id({pb, sb}), m_key(createKey(pb, sb, broadcast)),
       m_data(data), m_deleteData(deleteData),
       m_pollPriority(0),
-      m_usedByCondition(false), m_isScanMessage(true), m_condition(nullptr),
+      m_usedByCondition(false), m_isScanMessage(true), m_condition(nullptr), m_availableSinceTime(0),
       m_lastUpdateTime(0), m_lastChangeTime(0), m_pollOrder(0), m_lastPollTime(0) {
   time(&m_createTime);
 }
@@ -652,6 +652,19 @@ bool Message::isAvailable() {
   return (m_condition == nullptr) || m_condition->isTrue();
 }
 
+time_t Message::getAvailableSinceTime() {
+  if (m_condition == nullptr) {
+    return m_createTime;
+  }
+  if (!m_condition->isTrue()) {
+    return 0;
+  }
+  if (m_availableSinceTime == 0) {  // was not yet available
+    m_availableSinceTime = m_condition->getLastCheckTime();
+  }
+  return m_availableSinceTime;
+}
+
 bool Message::hasField(const char* fieldName, bool numeric) const {
   return m_data->hasField(fieldName, numeric);
 }
diff --git a/src/lib/ebus/message.h b/src/lib/ebus/message.h
index 647539f7..21e8118b 100644
--- a/src/lib/ebus/message.h
+++ b/src/lib/ebus/message.h
@@ -399,6 +399,12 @@ class Message : public AttributedItem {
    */
   bool isAvailable();
 
+  /**
+   * Get the time when this (potentially conditional) message first became available.
+   * @return the time when this message first became available, or 0 if it is not available.
+   */
+  time_t getAvailableSinceTime();
+
   /**
    * Return whether the field is available.
    * @param fieldName the name of the field to find, or nullptr for any.
@@ -673,6 +679,9 @@ class Message : public AttributedItem {
   /** the @a Condition for this message, or nullptr. */
   Condition* m_condition;
 
+  /** the time when the @a Condition first became available, or 0. */
+  time_t m_availableSinceTime;
+
   /** the last seen @a MasterSymbolString. */
   MasterSymbolString m_lastMasterData;
 
@@ -927,6 +936,12 @@ class Condition {
    */
   virtual bool isTrue() = 0;
 
+  /**
+   * Get the system time when the condition was last checked.
+   * @return the system time when the condition was last checked, 0 for never.
+   */
+  time_t getLastCheckTime() const { return m_lastCheckTime; }
+
 
  protected:
   /** the system time when the condition was last checked, 0 for never. */