diff --git a/tasmota/support.ino b/tasmota/support.ino
index ccf3bdf8d..170f7f819 100644
--- a/tasmota/support.ino
+++ b/tasmota/support.ino
@@ -1170,36 +1170,80 @@ char* ResponseGetTime(uint32_t format, char* time_str)
 }
 
 uint32_t ResponseSize(void) {
+#ifdef MQTT_DATA_STRING
+  return MESSZ;
+#else
   return sizeof(TasmotaGlobal.mqtt_data);
+#endif
 }
 
 uint32_t ResponseLength(void) {
+#ifdef MQTT_DATA_STRING
+  return TasmotaGlobal.mqtt_data.length();
+#else
   return strlen(TasmotaGlobal.mqtt_data);
+#endif
 }
 
 void ResponseClear(void) {
   // Reset string length to zero
+#ifdef MQTT_DATA_STRING
+  TasmotaGlobal.mqtt_data = "";
+#else
   TasmotaGlobal.mqtt_data[0] = '\0';
+#endif
 }
 
 void ResponseJsonStart(void) {
   // Insert a JSON start bracket {
+#ifdef MQTT_DATA_STRING
+  TasmotaGlobal.mqtt_data.setCharAt(0,'{');
+#else
   TasmotaGlobal.mqtt_data[0] = '{';
+#endif
 }
 
 int Response_P(const char* format, ...)        // Content send snprintf_P char data
 {
   // This uses char strings. Be aware of sending %% if % is needed
+#ifdef MQTT_DATA_STRING
+  va_list arg;
+  va_start(arg, format);
+  char* mqtt_data = ext_vsnprintf_malloc_P(format, arg);
+  va_end(arg);
+  if (mqtt_data != nullptr) {
+    TasmotaGlobal.mqtt_data = mqtt_data;
+    free(mqtt_data);
+  } else {
+    TasmotaGlobal.mqtt_data = "";
+  }
+  return TasmotaGlobal.mqtt_data.length();
+#else
   va_list args;
   va_start(args, format);
   int len = ext_vsnprintf_P(TasmotaGlobal.mqtt_data, ResponseSize(), format, args);
   va_end(args);
   return len;
+#endif
 }
 
 int ResponseTime_P(const char* format, ...)    // Content send snprintf_P char data
 {
   // This uses char strings. Be aware of sending %% if % is needed
+#ifdef MQTT_DATA_STRING
+  char timestr[100];
+  TasmotaGlobal.mqtt_data = ResponseGetTime(Settings.flag2.time_format, timestr);
+
+  va_list arg;
+  va_start(arg, format);
+  char* mqtt_data = ext_vsnprintf_malloc_P(format, arg);
+  va_end(arg);
+  if (mqtt_data != nullptr) {
+    TasmotaGlobal.mqtt_data += mqtt_data;
+    free(mqtt_data);
+  }
+  return TasmotaGlobal.mqtt_data.length();
+#else
   va_list args;
   va_start(args, format);
 
@@ -1209,17 +1253,30 @@ int ResponseTime_P(const char* format, ...)    // Content send snprintf_P char d
   int len = ext_vsnprintf_P(TasmotaGlobal.mqtt_data + mlen, ResponseSize() - mlen, format, args);
   va_end(args);
   return len + mlen;
+#endif
 }
 
 int ResponseAppend_P(const char* format, ...)  // Content send snprintf_P char data
 {
   // This uses char strings. Be aware of sending %% if % is needed
+#ifdef MQTT_DATA_STRING
+  va_list arg;
+  va_start(arg, format);
+  char* mqtt_data = ext_vsnprintf_malloc_P(format, arg);
+  va_end(arg);
+  if (mqtt_data != nullptr) {
+    TasmotaGlobal.mqtt_data += mqtt_data;
+    free(mqtt_data);
+  }
+  return TasmotaGlobal.mqtt_data.length();
+#else
   va_list args;
   va_start(args, format);
   int mlen = ResponseLength();
   int len = ext_vsnprintf_P(TasmotaGlobal.mqtt_data + mlen, ResponseSize() - mlen, format, args);
   va_end(args);
   return len + mlen;
+#endif
 }
 
 int ResponseAppendTimeFormat(uint32_t format)
@@ -1253,7 +1310,11 @@ int ResponseJsonEndEnd(void)
 }
 
 bool ResponseContains_P(const char* needle) {
+#ifdef MQTT_DATA_STRING
+  return (strstr_P(TasmotaGlobal.mqtt_data.c_str(), needle) != nullptr);
+#else
   return (strstr_P(TasmotaGlobal.mqtt_data, needle) != nullptr);
+#endif
 }
 
 /*********************************************************************************************\
diff --git a/tasmota/support_tasmota.ino b/tasmota/support_tasmota.ino
index b01d87ff4..d48878b39 100644
--- a/tasmota/support_tasmota.ino
+++ b/tasmota/support_tasmota.ino
@@ -1137,7 +1137,7 @@ void Every250mSeconds(void)
             char *bch = strrchr(full_ota_url, '/');         // Only consider filename after last backslash prevent change of urls having "-" in it
             if (bch == nullptr) { bch = full_ota_url; }     // No path found so use filename only
             char *ech = strchr(bch, '.');                              // Find file type in filename (none, .ino.bin, .ino.bin.gz, .bin, .bin.gz or .gz)
-            if (ech == nullptr) { ech = full_ota_url + strlen(full_ota_url); }  // Point to '/0' at end of mqtt_data becoming an empty string
+            if (ech == nullptr) { ech = full_ota_url + strlen(full_ota_url); }  // Point to '/0' at end of full_ota_url becoming an empty string
 
 //AddLog(LOG_LEVEL_DEBUG, PSTR("OTA: File type [%s]"), ech);
 
@@ -1146,7 +1146,7 @@ void Every250mSeconds(void)
 
             char *pch = strrchr(bch, '-');                             // Find last dash (-) and ignore remainder - handles tasmota-DE
             if (pch == nullptr) { pch = ech; }                         // No dash so ignore filetype
-            *pch = '\0';                                               // mqtt_data = http://domus1:80/api/arduino/tasmota
+            *pch = '\0';                                               // full_ota_url = http://domus1:80/api/arduino/tasmota
             snprintf_P(full_ota_url, sizeof(full_ota_url), PSTR("%s-" D_JSON_MINIMAL "%s"), full_ota_url, ota_url_type);  // Minimal filename must be filename-minimal
           }
 #endif  // FIRMWARE_MINIMAL
diff --git a/tasmota/tasmota.ino b/tasmota/tasmota.ino
index 4c09c733f..3e6549424 100644
--- a/tasmota/tasmota.ino
+++ b/tasmota/tasmota.ino
@@ -196,13 +196,18 @@ struct {
   String backlog[MAX_BACKLOG];              // Command backlog buffer
 #endif
 
+#ifdef MQTT_DATA_STRING
+  String mqtt_data;                         // Buffer filled by Response functions
+#else
+  char mqtt_data[MESSZ];                    // MQTT publish buffer
+#endif
+
   char version[16];                         // Composed version string like 255.255.255.255
   char image_name[33];                      // Code image and/or commit
   char hostname[33];                        // Composed Wifi hostname
   char serial_in_buffer[INPUT_BUFFER_SIZE];  // Receive buffer
   char mqtt_client[99];                     // Composed MQTT Clientname
   char mqtt_topic[TOPSZ];                   // Composed MQTT topic
-  char mqtt_data[MESSZ];                    // MQTT publish buffer and web page ajax buffer
   char log_buffer[LOG_BUFFER_SIZE];         // Web log buffer
 } TasmotaGlobal;
 
diff --git a/tasmota/tasmota_globals.h b/tasmota/tasmota_globals.h
index 60e4b3f80..2dea686d5 100644
--- a/tasmota/tasmota_globals.h
+++ b/tasmota/tasmota_globals.h
@@ -266,6 +266,8 @@ const uint16_t LOG_BUFFER_SIZE = 4000;         // Max number of characters in lo
 #define TASM_FILE_AUTOEXEC          "/autoexec.bat"    // Commands executed after restart
 #define TASM_FILE_CONFIG            "/config.sys"      // Settings executed after restart
 
+#define MQTT_DATA_STRING                               // Use heap instead of fixed memory for TasmotaGlobal.mqtt_data
+
 #ifndef MQTT_MAX_PACKET_SIZE
 #define MQTT_MAX_PACKET_SIZE        1200       // Bytes
 //#define MQTT_MAX_PACKET_SIZE        2048       // Bytes
diff --git a/tasmota/xdrv_01_webserver.ino b/tasmota/xdrv_01_webserver.ino
index 64ebf2378..52f4cb72e 100644
--- a/tasmota/xdrv_01_webserver.ino
+++ b/tasmota/xdrv_01_webserver.ino
@@ -2070,7 +2070,11 @@ void HandleOtherConfiguration(void) {
   WSContentSendStyle();
 
   TemplateJson();
+#ifdef MQTT_DATA_STRING
+  WSContentSend_P(HTTP_FORM_OTHER, TasmotaGlobal.mqtt_data.c_str(), (USER_MODULE == Settings.module) ? PSTR(" checked disabled") : "",
+#else
   WSContentSend_P(HTTP_FORM_OTHER, TasmotaGlobal.mqtt_data, (USER_MODULE == Settings.module) ? PSTR(" checked disabled") : "",
+#endif
     (Settings.flag.mqtt_enabled) ? PSTR(" checked") : "",   // SetOption3 - Enable MQTT
     SettingsText(SET_FRIENDLYNAME1), SettingsText(SET_DEVICENAME));
 
diff --git a/tasmota/xdrv_02_9_mqtt.ino b/tasmota/xdrv_02_9_mqtt.ino
index eaf8f6ce6..bd43f57c9 100644
--- a/tasmota/xdrv_02_9_mqtt.ino
+++ b/tasmota/xdrv_02_9_mqtt.ino
@@ -604,8 +604,6 @@ void MqttPublishLoggingAsync(bool refresh) {
   while (GetLog(Settings.mqttlog_level, &index, &line, &len)) {
     char stopic[TOPSZ];
     GetTopic_P(stopic, STAT, TasmotaGlobal.mqtt_topic, PSTR("LOGGING"));
-//    strlcpy(TasmotaGlobal.mqtt_data, line, len);  // No JSON and ugly!!
-//    MqttPublishLib(stopic, (const uint8_t*)TasmotaGlobal.mqtt_data, ResponseLength(), false);
     MqttPublishLib(stopic, (const uint8_t*)line, len -1, false);
   }
 }
@@ -652,7 +650,11 @@ void MqttPublishPayload(const char* topic, const char* payload) {
 
 void MqttPublish(const char* topic, bool retained) {
   // Publish <topic> default TasmotaGlobal.mqtt_data string with optional retained
+#ifdef MQTT_DATA_STRING
+  MqttPublishPayload(topic, TasmotaGlobal.mqtt_data.c_str(), 0, retained);
+#else
   MqttPublishPayload(topic, TasmotaGlobal.mqtt_data, 0, retained);
+#endif
 }
 
 void MqttPublish(const char* topic) {
@@ -734,7 +736,11 @@ void MqttPublishPayloadPrefixTopicRulesProcess_P(uint32_t prefix, const char* su
 
 void MqttPublishPrefixTopic_P(uint32_t prefix, const char* subtopic, bool retained) {
   // Publish <prefix>/<device>/<RESULT or <subtopic>> default TasmotaGlobal.mqtt_data string with optional retained
+#ifdef MQTT_DATA_STRING
+  MqttPublishPayloadPrefixTopic_P(prefix, subtopic, TasmotaGlobal.mqtt_data.c_str(), 0, retained);
+#else
   MqttPublishPayloadPrefixTopic_P(prefix, subtopic, TasmotaGlobal.mqtt_data, 0, retained);
+#endif
 }
 
 void MqttPublishPrefixTopic_P(uint32_t prefix, const char* subtopic) {
@@ -1045,9 +1051,17 @@ void MqttReconnect(void) {
   }
 
   String azureMqtt_userString = String(SettingsText(SET_MQTT_HOST)) + "/" + String(SettingsText(SET_MQTT_CLIENT)); + "/?api-version=2018-06-30";
+#ifdef MQTT_DATA_STRING
+  if (MqttClient.connect(TasmotaGlobal.mqtt_client, azureMqtt_userString.c_str(), azureMqtt_password.c_str(), stopic, 1, lwt_retain, TasmotaGlobal.mqtt_data.c_str(), MQTT_CLEAN_SESSION)) {
+#else
   if (MqttClient.connect(TasmotaGlobal.mqtt_client, azureMqtt_userString.c_str(), azureMqtt_password.c_str(), stopic, 1, lwt_retain, TasmotaGlobal.mqtt_data, MQTT_CLEAN_SESSION)) {
+#endif
+#else
+#ifdef MQTT_DATA_STRING
+  if (MqttClient.connect(TasmotaGlobal.mqtt_client, mqtt_user, mqtt_pwd, stopic, 1, lwt_retain, TasmotaGlobal.mqtt_data.c_str(), MQTT_CLEAN_SESSION)) {
 #else
   if (MqttClient.connect(TasmotaGlobal.mqtt_client, mqtt_user, mqtt_pwd, stopic, 1, lwt_retain, TasmotaGlobal.mqtt_data, MQTT_CLEAN_SESSION)) {
+#endif
 #endif  // USE_MQTT_AZURE_IOT
 #ifdef USE_MQTT_TLS
     if (Mqtt.mqtt_tls) {
diff --git a/tasmota/xdrv_10_rules.ino b/tasmota/xdrv_10_rules.ino
index a0b114f1b..7fbdde313 100644
--- a/tasmota/xdrv_10_rules.ino
+++ b/tasmota/xdrv_10_rules.ino
@@ -797,7 +797,7 @@ bool RuleSetProcess(uint8_t rule_set, String &event_saved)
 
 /*******************************************************************************************/
 
-bool RulesProcessEvent(char *json_event)
+bool RulesProcessEvent(const char *json_event)
 {
   if (Rules.busy) { return false; }
 
@@ -986,7 +986,11 @@ void RulesEvery100ms(void) {
     if (ResponseLength()) {
       ResponseJsonStart();                                           // {"INA219":{"Voltage":4.494,"Current":0.020,"Power":0.089}
       ResponseJsonEnd();
+#ifdef MQTT_DATA_STRING
+      RulesProcessEvent(TasmotaGlobal.mqtt_data.c_str());
+#else
       RulesProcessEvent(TasmotaGlobal.mqtt_data);
+#endif
     }
   }
 }
diff --git a/tasmota/xdrv_10_scripter.ino b/tasmota/xdrv_10_scripter.ino
index 1fb0341fe..f5105a35f 100755
--- a/tasmota/xdrv_10_scripter.ino
+++ b/tasmota/xdrv_10_scripter.ino
@@ -2401,7 +2401,11 @@ chknext:
           char rstring[SCRIPT_MAXSSIZE];
           rstring[0] = 0;
           int8_t index = fvar;
+#ifdef MQTT_DATA_STRING
           char *wd = TasmotaGlobal.mqtt_data;
+#else
+          char *wd = TasmotaGlobal.mqtt_data.c_str();
+#endif
           strlcpy(rstring, wd, glob_script_mem.max_ssize);
           if (index) {
             if (strlen(wd) && index) {
@@ -2426,7 +2430,11 @@ chknext:
                 // preserve mqtt_data
                 char *mqd = (char*)malloc(ResponseSize()+2);
                 if (mqd) {
+#ifdef MQTT_DATA_STRING
+                  strlcpy(mqd, TasmotaGlobal.mqtt_data.c_str(), ResponseSize());
+#else
                   strlcpy(mqd, TasmotaGlobal.mqtt_data, ResponseSize());
+#endif
                   wd = mqd;
                   char *lwd = wd;
                   while (index) {
@@ -4982,7 +4990,11 @@ void ScripterEvery100ms(void) {
     if (ResponseLength()) {
       ResponseJsonStart();
       ResponseJsonEnd();
+#ifdef MQTT_DATA_STRING
+      Run_Scripter(">T", 2, TasmotaGlobal.mqtt_data.c_str());
+#else
       Run_Scripter(">T", 2, TasmotaGlobal.mqtt_data);
+#endif
     }
   }
   if (bitRead(Settings.rule_enabled, 0)) {
@@ -7567,7 +7579,7 @@ void ScriptJsonAppend(void) {
 #endif //USE_SCRIPT_JSON_EXPORT
 
 
-bool RulesProcessEvent(char *json_event) {
+bool RulesProcessEvent(const char *json_event) {
   if (bitRead(Settings.rule_enabled, 0)) Run_Scripter(">E", 2, json_event);
   return true;
 }
@@ -7703,9 +7715,15 @@ int32_t http_req(char *host, char *request) {
   }
 
 #ifdef USE_WEBSEND_RESPONSE
+#ifdef MQTT_DATA_STRING
+  TasmotaGlobal.mqtt_data = http.getString();
+  //AddLog(LOG_LEVEL_INFO, PSTR("HTTP RESULT %s"), TasmotaGlobal.mqtt_data.c_str());
+  Run_Scripter(">E", 2, TasmotaGlobal.mqtt_data.c_str());
+#else
   strlcpy(TasmotaGlobal.mqtt_data, http.getString().c_str(), ResponseSize());
   //AddLog(LOG_LEVEL_INFO, PSTR("HTTP RESULT %s"), TasmotaGlobal.mqtt_data);
   Run_Scripter(">E", 2, TasmotaGlobal.mqtt_data);
+#endif
   glob_script_mem.glob_error = 0;
 #endif
 
@@ -8405,6 +8423,17 @@ bool Xdrv10(uint8_t function)
       break;
     case FUNC_RULES_PROCESS:
       if (bitRead(Settings.rule_enabled, 0)) {
+#ifdef MQTT_DATA_STRING
+#ifdef USE_SCRIPT_STATUS
+        if (!strncmp_P(TasmotaGlobal.mqtt_data.c_str(), PSTR("{\"Status"), 8)) {
+          Run_Scripter(">U", 2, TasmotaGlobal.mqtt_data.c_str());
+        } else {
+          Run_Scripter(">E", 2, TasmotaGlobal.mqtt_data.c_str());
+        }
+#else
+        Run_Scripter(">E", 2, TasmotaGlobal.mqtt_data.c_str());
+#endif
+#else  // MQTT_DATA_STRING
 #ifdef USE_SCRIPT_STATUS
         if (!strncmp_P(TasmotaGlobal.mqtt_data, PSTR("{\"Status"), 8)) {
           Run_Scripter(">U", 2, TasmotaGlobal.mqtt_data);
@@ -8414,14 +8443,21 @@ bool Xdrv10(uint8_t function)
 #else
         Run_Scripter(">E", 2, TasmotaGlobal.mqtt_data);
 #endif
+#endif  // MQTT_DATA_STRING
         result = glob_script_mem.event_handeled;
       }
       break;
     case FUNC_TELEPERIOD_RULES_PROCESS:
       if (bitRead(Settings.rule_enabled, 0)) {
+#ifdef MQTT_DATA_STRING
+        if (TasmotaGlobal.mqtt_data.length()) {
+          Run_Scripter(">T", 2, TasmotaGlobal.mqtt_data.c_str());
+        }
+#else
         if (TasmotaGlobal.mqtt_data[0]) {
           Run_Scripter(">T", 2, TasmotaGlobal.mqtt_data);
         }
+#endif
       }
       break;
 #ifdef USE_WEBSERVER
diff --git a/tasmota/xdrv_12_home_assistant.ino b/tasmota/xdrv_12_home_assistant.ino
index 08db2aaac..36fa9bd22 100644
--- a/tasmota/xdrv_12_home_assistant.ino
+++ b/tasmota/xdrv_12_home_assistant.ino
@@ -355,8 +355,17 @@ void NewHAssDiscovery(void)
 
 // NEW DISCOVERY
 
-void TryResponseAppend_P(const char *format, ...)
-{
+void TryResponseAppend_P(const char *format, ...) {
+#ifdef MQTT_DATA_STRING
+  va_list arg;
+  va_start(arg, format);
+  char* mqtt_data = ext_vsnprintf_malloc_P(format, arg);
+  va_end(arg);
+  if (mqtt_data != nullptr) {
+    TasmotaGlobal.mqtt_data += mqtt_data;
+    free(mqtt_data);
+  }
+#else
   va_list args;
   va_start(args, format);
   char dummy[2];
@@ -378,6 +387,7 @@ void TryResponseAppend_P(const char *format, ...)
     vsnprintf_P(TasmotaGlobal.mqtt_data + mlen, slen, format, args);
   }
   va_end(args);
+#endif
 }
 
 void HAssAnnounceRelayLight(void)
diff --git a/tasmota/xdrv_13_display.ino b/tasmota/xdrv_13_display.ino
index b7bbb90cb..05071034e 100755
--- a/tasmota/xdrv_13_display.ino
+++ b/tasmota/xdrv_13_display.ino
@@ -1301,7 +1301,11 @@ void DisplayDTVarsTeleperiod(void) {
   if (jlen < DTV_JSON_SIZE) {
     char *json = (char*)malloc(jlen + 2);
     if (json) {
+#ifdef MQTT_DATA_STRING
+      strlcpy(json, TasmotaGlobal.mqtt_data.c_str(), jlen + 1);
+#else
       strlcpy(json, TasmotaGlobal.mqtt_data, jlen + 1);
+#endif
       get_dt_vars(json);
       free(json);
     }
@@ -1320,7 +1324,11 @@ void get_dt_mqtt(void) {
     ResponseJsonStart();
     ResponseJsonEnd();
   }
+#ifdef MQTT_DATA_STRING
+  get_dt_vars(TasmotaGlobal.mqtt_data.c_str());
+#else
   get_dt_vars(TasmotaGlobal.mqtt_data);
+#endif
 }
 
 void get_dt_vars(char *json) {
@@ -1737,8 +1745,13 @@ void DisplayLocalSensor(void)
 {
   if ((Settings.display_mode &0x02) && (0 == TasmotaGlobal.tele_period)) {
     char no_topic[1] = { 0 };
+#ifdef MQTT_DATA_STRING
+//    DisplayAnalyzeJson(TasmotaGlobal.mqtt_topic, TasmotaGlobal.mqtt_data.c_str());  // Add local topic
+    DisplayAnalyzeJson(no_topic, TasmotaGlobal.mqtt_data.c_str());    // Discard any topic
+#else
 //    DisplayAnalyzeJson(TasmotaGlobal.mqtt_topic, TasmotaGlobal.mqtt_data);  // Add local topic
     DisplayAnalyzeJson(no_topic, TasmotaGlobal.mqtt_data);    // Discard any topic
+#endif
   }
 }
 
diff --git a/tasmota/xdrv_16_tuyamcu.ino b/tasmota/xdrv_16_tuyamcu.ino
index 92c8178e8..295860c33 100644
--- a/tasmota/xdrv_16_tuyamcu.ino
+++ b/tasmota/xdrv_16_tuyamcu.ino
@@ -1227,7 +1227,11 @@ void TuyaSerialInput(void)
       if (Settings.flag3.tuya_serial_mqtt_publish) {  // SetOption66 - Enable TuyaMcuReceived messages over Mqtt
         MqttPublishPrefixTopic_P(RESULT_OR_TELE, PSTR(D_JSON_TUYA_MCU_RECEIVED));
       } else {
+#ifdef MQTT_DATA_STRING
+        AddLog(LOG_LEVEL_DEBUG, TasmotaGlobal.mqtt_data.c_str());
+#else
         AddLog(LOG_LEVEL_DEBUG, TasmotaGlobal.mqtt_data);
+#endif
       }
       XdrvRulesProcess(0);
 
diff --git a/tasmota/xdrv_23_zigbee_5_converters.ino b/tasmota/xdrv_23_zigbee_5_converters.ino
index 583c13307..ab6bf44d0 100644
--- a/tasmota/xdrv_23_zigbee_5_converters.ino
+++ b/tasmota/xdrv_23_zigbee_5_converters.ino
@@ -751,7 +751,11 @@ public:
     if (Settings.flag3.tuya_serial_mqtt_publish) {
       MqttPublishPrefixTopicRulesProcess_P(TELE, PSTR(D_RSLT_SENSOR));
     } else {
+#ifdef MQTT_DATA_STRING
+      AddLog(LOG_LEVEL_DEBUG, PSTR(D_LOG_ZIGBEE "%s"), TasmotaGlobal.mqtt_data.c_str());
+#else
       AddLog(LOG_LEVEL_DEBUG, PSTR(D_LOG_ZIGBEE "%s"), TasmotaGlobal.mqtt_data);
+#endif      
     }
   }
 
diff --git a/tasmota/xdrv_23_zigbee_8_parsers.ino b/tasmota/xdrv_23_zigbee_8_parsers.ino
index 2d13b1e62..578b4c733 100644
--- a/tasmota/xdrv_23_zigbee_8_parsers.ino
+++ b/tasmota/xdrv_23_zigbee_8_parsers.ino
@@ -1577,7 +1577,11 @@ void Z_AutoConfigReportingForCluster(uint16_t shortaddr, uint16_t groupaddr, uin
   ResponseAppend_P(PSTR("}}"));
 
   if (buf.len() > 0) {
+#ifdef MQTT_DATA_STRING
+    AddLog(LOG_LEVEL_INFO, PSTR(D_LOG_ZIGBEE "auto-bind `%s`"), TasmotaGlobal.mqtt_data.c_str());
+#else
     AddLog(LOG_LEVEL_INFO, PSTR(D_LOG_ZIGBEE "auto-bind `%s`"), TasmotaGlobal.mqtt_data);
+#endif
     ZCLMessage zcl(buf.len());   // message is 4 bytes
     zcl.shortaddr = shortaddr;
     zcl.cluster = cluster;
diff --git a/tasmota/xdrv_23_zigbee_9_serial.ino b/tasmota/xdrv_23_zigbee_9_serial.ino
index 814f137a1..12442d200 100644
--- a/tasmota/xdrv_23_zigbee_9_serial.ino
+++ b/tasmota/xdrv_23_zigbee_9_serial.ino
@@ -152,7 +152,11 @@ void ZigbeeInputLoop(void) {
       if (Settings.flag3.tuya_serial_mqtt_publish) {
         MqttPublishPrefixTopicRulesProcess_P(TELE, PSTR(D_RSLT_SENSOR));
       } else {
+#ifdef MQTT_DATA_STRING
+        AddLog(LOG_LEVEL_DEBUG, PSTR(D_LOG_ZIGBEE "%s"), TasmotaGlobal.mqtt_data.c_str());
+#else
         AddLog(LOG_LEVEL_DEBUG, PSTR(D_LOG_ZIGBEE "%s"), TasmotaGlobal.mqtt_data);
+#endif        
       }
 			// now process the message
       ZigbeeProcessInput(znp_buffer);
@@ -597,7 +601,11 @@ void ZigbeeProcessInputEZSP(SBuffer &buf) {
         log_level = LOG_LEVEL_DEBUG;
         break;
     }
+#ifdef MQTT_DATA_STRING
+    AddLog(log_level, PSTR(D_LOG_ZIGBEE "%s"), TasmotaGlobal.mqtt_data.c_str());    // TODO move to LOG_LEVEL_DEBUG when stable
+#else
     AddLog(log_level, PSTR(D_LOG_ZIGBEE "%s"), TasmotaGlobal.mqtt_data);    // TODO move to LOG_LEVEL_DEBUG when stable
+#endif    
   }
 
   // Pass message to state machine
diff --git a/tasmota/xdrv_52_3_berry_tasmota.ino b/tasmota/xdrv_52_3_berry_tasmota.ino
index 75d5d359e..4aedf3330 100644
--- a/tasmota/xdrv_52_3_berry_tasmota.ino
+++ b/tasmota/xdrv_52_3_berry_tasmota.ino
@@ -97,7 +97,11 @@ extern "C" {
       const char * command = be_tostring(vm, 2);
       be_pop(vm, 2);    // clear the stack before calling, because of re-entrant call to Berry in a Rule
       ExecuteCommand(command, SRC_BERRY);
+#ifdef MQTT_DATA_STRING
+      be_pushstring(vm, TasmotaGlobal.mqtt_data.c_str());
+#else
       be_pushstring(vm, TasmotaGlobal.mqtt_data);
+#endif
       be_return(vm); // Return
     }
     be_raise(vm, kTypeError, nullptr);
diff --git a/tasmota/xdrv_interface.ino b/tasmota/xdrv_interface.ino
index 79035ef9c..c0d99d71e 100644
--- a/tasmota/xdrv_interface.ino
+++ b/tasmota/xdrv_interface.ino
@@ -1093,7 +1093,11 @@ bool XdrvRulesProcess(bool teleperiod, const char* payload) {
 }
 
 bool XdrvRulesProcess(bool teleperiod) {
+#ifdef MQTT_DATA_STRING
+  return XdrvRulesProcess(teleperiod, TasmotaGlobal.mqtt_data.c_str());
+#else
   return XdrvRulesProcess(teleperiod, TasmotaGlobal.mqtt_data);
+#endif  
 }
 
 #ifdef USE_DEBUG_DRIVER
diff --git a/tasmota/xsns_62_esp32_mi_ble.ino b/tasmota/xsns_62_esp32_mi_ble.ino
index db1675098..aa99a6e80 100644
--- a/tasmota/xsns_62_esp32_mi_ble.ino
+++ b/tasmota/xsns_62_esp32_mi_ble.ino
@@ -2689,7 +2689,11 @@ void MI32ShowSomeSensors(){
   }
   ResponseAppend_P(PSTR("}"));
   MqttPublishPrefixTopicRulesProcess_P(TELE, PSTR(D_RSLT_SENSOR), Settings.flag.mqtt_sensor_retain);
+#ifdef MQTT_DATA_STRING
+  //AddLog(LOG_LEVEL_DEBUG,PSTR("M32: %s: show some %d %s"),D_CMND_MI32, MI32.mqttCurrentSlot, TasmotaGlobal.mqtt_data.c_str());
+#else
   //AddLog(LOG_LEVEL_DEBUG,PSTR("M32: %s: show some %d %s"),D_CMND_MI32, MI32.mqttCurrentSlot, TasmotaGlobal.mqtt_data);
+#endif
 
 #ifdef USE_HOME_ASSISTANT
   if(hass_mode==2){
@@ -2742,7 +2746,11 @@ void MI32ShowOneMISensor(){
       id);
 
     MqttPublish(SensorTopic);
+#ifdef MQTT_DATA_STRING
+    //AddLog(LOG_LEVEL_DEBUG,PSTR("M32: %s: show some %d %s"),D_CMND_MI32, MI32.mqttCurrentSlot, TasmotaGlobal.mqtt_data.c_str());
+#else
     //AddLog(LOG_LEVEL_DEBUG,PSTR("M32: %s: show some %d %s"),D_CMND_MI32, MI32.mqttCurrentSlot, TasmotaGlobal.mqtt_data);
+#endif
   }
   MI32.mqttCurrentSingleSlot++;
 }
@@ -2998,7 +3006,11 @@ void MI32DiscoveryOneMISensor(){
       //vTaskDelay(100/ portTICK_PERIOD_MS);
     }
   } // end if hass discovery
+#ifdef MQTT_DATA_STRING
+  //AddLog(LOG_LEVEL_DEBUG,PSTR("M32: %s: show some %d %s"),D_CMND_MI32, MI32.mqttCurrentSlot, TasmotaGlobal.mqtt_data.c_str());
+#else
   //AddLog(LOG_LEVEL_DEBUG,PSTR("M32: %s: show some %d %s"),D_CMND_MI32, MI32.mqttCurrentSlot, TasmotaGlobal.mqtt_data);
+#endif
 #endif //USE_HOME_ASSISTANT
 
 }
@@ -3076,8 +3088,11 @@ void MI32ShowTriggeredSensors(){
       } else {
         MqttPublishPrefixTopic_P(STAT, PSTR(D_RSLT_SENSOR), Settings.flag.mqtt_sensor_retain);
       }
+#ifdef MQTT_DATA_STRING
+      AddLog(LOG_LEVEL_DEBUG,PSTR("M32: %s: triggered %d %s"),D_CMND_MI32, sensor, TasmotaGlobal.mqtt_data.c_str());
+#else
       AddLog(LOG_LEVEL_DEBUG,PSTR("M32: %s: triggered %d %s"),D_CMND_MI32, sensor, TasmotaGlobal.mqtt_data);
-
+#endif
       XdrvRulesProcess(0);
 
     } else { // else don't and clear