diff --git a/src/CHANGES.md b/src/CHANGES.md
index 813f1708e..f0491335f 100644
--- a/src/CHANGES.md
+++ b/src/CHANGES.md
@@ -1,5 +1,8 @@
 # Development Changes
 
+## 0.8.74 - 2024-02-05
+* reduced cppcheck linter warnings significantly
+
 ## 0.8.73 - 2024-02-03
 * fix nullpointer during communication #1401
 * added `max_power` to MqTT total values #1375
diff --git a/src/app.cpp b/src/app.cpp
index 4f49d93b2..d9b0f9332 100644
--- a/src/app.cpp
+++ b/src/app.cpp
@@ -13,7 +13,10 @@
 
 
 //-----------------------------------------------------------------------------
-app::app() : ah::Scheduler {} {}
+app::app() : ah::Scheduler {} {
+    memset(mVersion, 0, sizeof(char) * 12);
+    memset(mVersionModules, 0, sizeof(char) * 12);
+}
 
 
 //-----------------------------------------------------------------------------
@@ -228,7 +231,6 @@ void app::updateNtp(void) {
         onceAt(std::bind(&app::tickMidnight, this), midTrig, "midNi");
 
         if (mConfig->sys.schedReboot) {
-            uint32_t localTime = gTimezone.toLocal(mTimestamp);
             uint32_t rebootTrig = gTimezone.toUTC(localTime - (localTime % 86400) + 86410);  // reboot 10 secs after midnght
             if (rebootTrig <= mTimestamp) { //necessary for times other than midnight to prevent reboot loop
                rebootTrig += 86400;
@@ -301,9 +303,8 @@ void app::tickIVCommunication(void) {
     bool zeroValues = false;
     uint32_t nxtTrig = 0;
 
-    Inverter<> *iv;
     for(uint8_t i = 0; i < MAX_NUM_INVERTERS; i ++) {
-        iv = mSys.getInverterByPos(i);
+        Inverter<> *iv = mSys.getInverterByPos(i);
         if(NULL == iv)
             continue;
 
@@ -390,10 +391,9 @@ void app::tickMidnight(void) {
 
         // clear max values
         if(mConfig->inst.rstMaxValsMidNight) {
-            uint8_t pos;
             record_t<> *rec = iv->getRecordStruct(RealTimeRunData_Debug);
             for(uint8_t i = 0; i <= iv->channels; i++) {
-                pos = iv->getPosByChFld(i, FLD_MP, rec);
+                uint8_t pos = iv->getPosByChFld(i, FLD_MP, rec);
                 iv->setValue(pos, rec, 0.0f);
             }
         }
@@ -592,9 +592,8 @@ void app::updateLed(void) {
     uint8_t led_on = (mConfig->led.high_active) ? (mConfig->led.luminance) : (255-mConfig->led.luminance);
 
     if (mConfig->led.led[0] != DEF_PIN_OFF) {
-        Inverter<> *iv;
         for (uint8_t id = 0; id < mSys.getNumInverters(); id++) {
-            iv = mSys.getInverterByPos(id);
+            Inverter<> *iv = mSys.getInverterByPos(id);
             if (NULL != iv) {
                 if (iv->isProducing()) {
                     // turn on when at least one inverter is producing
diff --git a/src/app.h b/src/app.h
index b44d3781e..60be4d1d0 100644
--- a/src/app.h
+++ b/src/app.h
@@ -90,7 +90,7 @@ class app : public IApp, public ah::Scheduler {
         void handleIntr(void) {
             mNrfRadio.handleIntr();
         }
-        void* getRadioObj(bool nrf) {
+        void* getRadioObj(bool nrf) override {
             if(nrf)
                 return (void*)&mNrfRadio;
             else {
@@ -108,19 +108,19 @@ class app : public IApp, public ah::Scheduler {
         }
         #endif
 
-        uint32_t getUptime() {
+        uint32_t getUptime() override {
             return Scheduler::getUptime();
         }
 
-        uint32_t getTimestamp() {
+        uint32_t getTimestamp() override {
             return Scheduler::mTimestamp;
         }
 
-        uint64_t getTimestampMs() {
+        uint64_t getTimestampMs() override {
             return ((uint64_t)Scheduler::mTimestamp * 1000) + ((uint64_t)millis() - (uint64_t)Scheduler::mTsMillis) % 1000;
         }
 
-        bool saveSettings(bool reboot) {
+        bool saveSettings(bool reboot) override {
             mShowRebootRequest = true; // only message on index, no reboot
             mSavePending = true;
             mSaveReboot = reboot;
@@ -131,7 +131,7 @@ class app : public IApp, public ah::Scheduler {
             return true;
         }
 
-        void initInverter(uint8_t id) {
+        void initInverter(uint8_t id) override {
             mSys.addInverter(id, [this](Inverter<> *iv) {
                 if((IV_MI == iv->ivGen) || (IV_HM == iv->ivGen))
                     iv->radio = &mNrfRadio;
@@ -142,7 +142,7 @@ class app : public IApp, public ah::Scheduler {
             });
         }
 
-        bool readSettings(const char *path) {
+        bool readSettings(const char *path) override {
             return mSettings.readSettings(path);
         }
 
@@ -150,80 +150,80 @@ class app : public IApp, public ah::Scheduler {
             return mSettings.eraseSettings(eraseWifi);
         }
 
-        bool getSavePending() {
+        bool getSavePending() override {
             return mSavePending;
         }
 
-        bool getLastSaveSucceed() {
+        bool getLastSaveSucceed() override {
             return mSettings.getLastSaveSucceed();
         }
 
-        bool getShouldReboot() {
+        bool getShouldReboot() override {
             return mSaveReboot;
         }
 
         #if !defined(ETHERNET)
-        void scanAvailNetworks() {
+        void scanAvailNetworks() override {
             mWifi.scanAvailNetworks();
         }
 
-        bool getAvailNetworks(JsonObject obj) {
+        bool getAvailNetworks(JsonObject obj) override {
             return mWifi.getAvailNetworks(obj);
         }
 
-        void setupStation(void) {
+        void setupStation(void) override {
             mWifi.setupStation();
         }
 
-        void setStopApAllowedMode(bool allowed) {
+        void setStopApAllowedMode(bool allowed) override {
             mWifi.setStopApAllowedMode(allowed);
         }
 
-        String getStationIp(void) {
+        String getStationIp(void) override {
             return mWifi.getStationIp();
         }
 
-        bool getWasInCh12to14(void) const {
+        bool getWasInCh12to14(void) const override {
             return mWifi.getWasInCh12to14();
         }
 
         #endif /* !defined(ETHERNET) */
 
-        void setRebootFlag() {
+        void setRebootFlag() override {
             once(std::bind(&app::tickReboot, this), 3, "rboot");
         }
 
-        const char *getVersion() {
+        const char *getVersion() override {
             return mVersion;
         }
 
-        const char *getVersionModules() {
+        const char *getVersionModules() override {
             return mVersionModules;
         }
 
-        uint32_t getSunrise() {
+        uint32_t getSunrise() override {
             return mSunrise;
         }
 
-        uint32_t getSunset() {
+        uint32_t getSunset() override {
             return mSunset;
         }
 
-        bool getSettingsValid() {
+        bool getSettingsValid() override {
             return mSettings.getValid();
         }
 
-        bool getRebootRequestState() {
+        bool getRebootRequestState() override {
             return mShowRebootRequest;
         }
 
-        void setMqttDiscoveryFlag() {
+        void setMqttDiscoveryFlag() override {
             #if defined(ENABLE_MQTT)
             once(std::bind(&PubMqttType::sendDiscoveryConfig, &mMqtt), 1, "disCf");
             #endif
         }
 
-        bool getMqttIsConnected() {
+        bool getMqttIsConnected() override {
             #if defined(ENABLE_MQTT)
                 return mMqtt.isConnected();
             #else
@@ -231,7 +231,7 @@ class app : public IApp, public ah::Scheduler {
             #endif
         }
 
-        uint32_t getMqttTxCnt() {
+        uint32_t getMqttTxCnt() override {
             #if defined(ENABLE_MQTT)
                 return mMqtt.getTxCnt();
             #else
@@ -239,7 +239,7 @@ class app : public IApp, public ah::Scheduler {
             #endif
         }
 
-        uint32_t getMqttRxCnt() {
+        uint32_t getMqttRxCnt() override {
             #if defined(ENABLE_MQTT)
                 return mMqtt.getRxCnt();
             #else
@@ -267,11 +267,11 @@ class app : public IApp, public ah::Scheduler {
             return mProtection->isProtected(clientIp);
         }
 
-        bool getNrfEnabled(void) {
+        bool getNrfEnabled(void) override {
             return mConfig->nrf.enabled;
         }
 
-        bool getCmtEnabled(void) {
+        bool getCmtEnabled(void) override {
             return mConfig->cmt.enabled;
         }
 
@@ -283,19 +283,19 @@ class app : public IApp, public ah::Scheduler {
             return mConfig->cmt.pinIrq;
         }
 
-        uint32_t getTimezoneOffset() {
+        uint32_t getTimezoneOffset() override {
             return mApi.getTimezoneOffset();
         }
 
-        void getSchedulerInfo(uint8_t *max) {
+        void getSchedulerInfo(uint8_t *max) override {
             getStat(max);
         }
 
-        void getSchedulerNames(void) {
+        void getSchedulerNames(void) override {
             printSchedulers();
         }
 
-        void setTimestamp(uint32_t newTime) {
+        void setTimestamp(uint32_t newTime) override {
             DPRINT(DBG_DEBUG, F("setTimestamp: "));
             DBGPRINTLN(String(newTime));
             if(0 == newTime)
@@ -310,7 +310,7 @@ class app : public IApp, public ah::Scheduler {
                 Scheduler::setTimestamp(newTime);
         }
 
-        uint16_t getHistoryValue(uint8_t type, uint16_t i) {
+        uint16_t getHistoryValue(uint8_t type, uint16_t i) override {
             #if defined(ENABLE_HISTORY)
                 return mHistory.valueAt((HistoryStorageType)type, i);
             #else
@@ -318,7 +318,7 @@ class app : public IApp, public ah::Scheduler {
             #endif
         }
 
-        uint16_t getHistoryMaxDay() {
+        uint16_t getHistoryMaxDay() override {
             #if defined(ENABLE_HISTORY)
                 return mHistory.getMaximumDay();
             #else
@@ -372,11 +372,11 @@ class app : public IApp, public ah::Scheduler {
         void tickNtpUpdate(void);
         #if defined(ETHERNET)
         void onNtpUpdate(bool gotTime);
-        bool mNtpReceived;
+        bool mNtpReceived = false;
         #endif /* defined(ETHERNET) */
         void updateNtp(void);
 
-        void triggerTickSend() {
+        void triggerTickSend() override {
             once(std::bind(&app::tickSend, this), 0, "tSend");
         }
 
@@ -395,7 +395,7 @@ class app : public IApp, public ah::Scheduler {
         HmRadio<> mNrfRadio;
         Communication mCommunication;
 
-        bool mShowRebootRequest;
+        bool mShowRebootRequest = false;
 
         #if defined(ETHERNET)
         ahoyeth mEth;
@@ -404,7 +404,7 @@ class app : public IApp, public ah::Scheduler {
         #endif /* defined(ETHERNET) */
         WebType mWeb;
         RestApiType mApi;
-        Protection *mProtection;
+        Protection *mProtection = nullptr;
         #ifdef ENABLE_SYSLOG
         DbgSyslog mDbgSyslog;
         #endif
@@ -421,26 +421,26 @@ class app : public IApp, public ah::Scheduler {
         char mVersion[12];
         char mVersionModules[12];
         settings mSettings;
-        settings_t *mConfig;
-        bool mSavePending;
-        bool mSaveReboot;
+        settings_t *mConfig = nullptr;
+        bool mSavePending = false;
+        bool mSaveReboot = false;
 
-        uint8_t mSendLastIvId;
-        bool mSendFirst;
-        bool mAllIvNotAvail;
+        uint8_t mSendLastIvId = 0;
+        bool mSendFirst = false;
+        bool mAllIvNotAvail = false;
 
-        bool mNetworkConnected;
+        bool mNetworkConnected = false;
 
         // mqtt
         #if defined(ENABLE_MQTT)
         PubMqttType mMqtt;
         #endif /*ENABLE_MQTT*/
-        bool mMqttReconnect;
-        bool mMqttEnabled;
+        bool mMqttReconnect = false;
+        bool mMqttEnabled = false;
 
         // sun
-        int32_t mCalculatedTimezoneOffset;
-        uint32_t mSunrise, mSunset;
+        int32_t mCalculatedTimezoneOffset = 0;
+        uint32_t mSunrise = 0, mSunset = 0;
 
         // plugins
         #if defined(PLUGIN_DISPLAY)
diff --git a/src/config/settings.h b/src/config/settings.h
index ec9712ea1..0cb9ed4ee 100644
--- a/src/config/settings.h
+++ b/src/config/settings.h
@@ -13,6 +13,7 @@
 
 #include <Arduino.h>
 #include <ArduinoJson.h>
+#include <algorithm>
 #include <LittleFS.h>
 
 #include "../defines.h"
@@ -206,7 +207,7 @@ typedef struct {
 class settings {
     public:
         settings() {
-            mLastSaveSucceed = false;
+            std::fill(reinterpret_cast<char*>(&mCfg), reinterpret_cast<char*>(&mCfg) + sizeof(mCfg), 0);
         }
 
         void setup() {
@@ -377,7 +378,7 @@ class settings {
                 memcpy(&tmp, &mCfg.sys, sizeof(cfgSys_t));
             }
             // erase all settings and reset to default
-            memset(&mCfg, 0, sizeof(settings_t));
+            std::fill(reinterpret_cast<char*>(&mCfg), reinterpret_cast<char*>(&mCfg) + sizeof(mCfg), 0);
             mCfg.sys.protectionMask = DEF_PROT_INDEX | DEF_PROT_LIVE | DEF_PROT_SERIAL | DEF_PROT_SETUP
                                     | DEF_PROT_UPDATE | DEF_PROT_SYSTEM | DEF_PROT_API | DEF_PROT_MQTT | DEF_PROT_HISTORY;
             mCfg.sys.darkMode = false;
@@ -847,7 +848,7 @@ class settings {
     #endif
 
         settings_t mCfg;
-        bool mLastSaveSucceed;
+        bool mLastSaveSucceed = 0;
 };
 
 #endif /*__SETTINGS_H__*/
diff --git a/src/defines.h b/src/defines.h
index b71a1d253..bc9d24529 100644
--- a/src/defines.h
+++ b/src/defines.h
@@ -13,7 +13,7 @@
 //-------------------------------------
 #define VERSION_MAJOR       0
 #define VERSION_MINOR       8
-#define VERSION_PATCH       73
+#define VERSION_PATCH       74
 
 //-------------------------------------
 typedef struct {
diff --git a/src/hm/CommQueue.h b/src/hm/CommQueue.h
index acbe9a358..328309acd 100644
--- a/src/hm/CommQueue.h
+++ b/src/hm/CommQueue.h
@@ -91,7 +91,7 @@ class CommQueue {
             inc(&mRdPtr);
         }
 
-        void setTs(uint32_t *ts) {
+        void setTs(const uint32_t *ts) {
             mQueue[mRdPtr].ts = *ts;
         }
 
diff --git a/src/hm/Communication.h b/src/hm/Communication.h
index d1521f81b..326fb57ed 100644
--- a/src/hm/Communication.h
+++ b/src/hm/Communication.h
@@ -6,6 +6,7 @@
 #ifndef __COMMUNICATION_H__
 #define __COMMUNICATION_H__
 
+#include <array>
 #include "CommQueue.h"
 #include <Arduino.h>
 #include "../utils/crc.h"
@@ -194,8 +195,8 @@ class Communication : public CommQueue<> {
                                 q->iv->radio->mBufCtrl.pop();
                                 return; // don't wait for empty buffer
                             } else if(IV_MI == q->iv->ivGen) {
-                                if(parseMiFrame(p, q))
-                                    q->iv->curFrmCnt++;
+                                parseMiFrame(p, q);
+                                q->iv->curFrmCnt++;
                             }
                         } //else -> serial does not match
 
@@ -385,7 +386,7 @@ class Communication : public CommQueue<> {
             }
         }
 
-        inline bool validateIvSerial(uint8_t buf[], Inverter<> *iv) {
+        inline bool validateIvSerial(const uint8_t buf[], Inverter<> *iv) {
             uint8_t tmp[4];
             CP_U32_BigEndian(tmp, iv->radioId.u64 >> 8);
             for(uint8_t i = 0; i < 4; i++) {
@@ -435,7 +436,7 @@ class Communication : public CommQueue<> {
             return true;
         }
 
-        inline bool parseMiFrame(packet_t *p, const queue_s *q) {
+        inline void parseMiFrame(packet_t *p, const queue_s *q) {
             if((!mIsRetransmit && p->packet[9] == 0x00) && (p->millis < LIMIT_FAST_IV_MI)) //first frame is fast?
                 mHeu.setIvRetriesGood(q->iv,p->millis < LIMIT_VERYFAST_IV_MI);
             if ((p->packet[0] == MI_REQ_CH1 + ALL_FRAMES)
@@ -458,11 +459,9 @@ class Communication : public CommQueue<> {
                 rec->ts = q->ts;
                 miStsConsolidate(q, ((p->packet[0] == 0x88) ? 1 : 2), rec, p->packet[10], p->packet[12], p->packet[9], p->packet[11]);
             }
-
-            return true;
         }
 
-        inline bool parseDevCtrl(packet_t *p, const queue_s *q) {
+        inline bool parseDevCtrl(const packet_t *p, const queue_s *q) {
             switch(p->packet[12]) {
                 case ActivePowerContr:
                     if(p->packet[13] != 0x00)
@@ -524,7 +523,7 @@ class Communication : public CommQueue<> {
                 return false;
             }
 
-            memset(mPayload, 0, MAX_BUFFER);
+            mPayload.fill(0);
             int8_t rssi = -127;
             uint8_t len = 0;
 
@@ -547,19 +546,19 @@ class Communication : public CommQueue<> {
             DBGPRINT(String(len));
             if(*mPrintWholeTrace) {
                 DBGPRINT(F("): "));
-                ah::dumpBuf(mPayload, len);
+                ah::dumpBuf(mPayload.data(), len);
             } else
                 DBGPRINTLN(F(")"));
 
             if(GridOnProFilePara == q->cmd) {
-                q->iv->addGridProfile(mPayload, len);
+                q->iv->addGridProfile(mPayload.data(), len);
                 return true;
             }
 
             record_t<> *rec = q->iv->getRecordStruct(q->cmd);
             if(NULL == rec) {
                 if(GetLossRate == q->cmd) {
-                    q->iv->parseGetLossRate(mPayload, len);
+                    q->iv->parseGetLossRate(mPayload.data(), len);
                     return true;
                 } else
                     DPRINTLN(DBG_ERROR, F("record is NULL!"));
@@ -578,7 +577,7 @@ class Communication : public CommQueue<> {
 
             rec->ts = q->ts;
             for (uint8_t i = 0; i < rec->length; i++) {
-                q->iv->addValue(i, mPayload, rec);
+                q->iv->addValue(i, mPayload.data(), rec);
             }
             rec->mqttSentStatus = MqttSentStatus::NEW_DATA;
 
@@ -588,7 +587,7 @@ class Communication : public CommQueue<> {
             if(AlarmData == q->cmd) {
                 uint8_t i = 0;
                 while(1) {
-                    if(0 == q->iv->parseAlarmLog(i++, mPayload, len))
+                    if(0 == q->iv->parseAlarmLog(i++, mPayload.data(), len))
                         break;
                     if (NULL != mCbAlarm)
                         (mCbAlarm)(q->iv);
@@ -670,7 +669,7 @@ class Communication : public CommQueue<> {
             };
             */
 
-            if ( p->packet[9] == 0x00 ) {//first frame
+            if ( p->packet[9] == 0x00 ) { //first frame
                 //FLD_FW_VERSION
                 for (uint8_t i = 0; i < 5; i++) {
                     q->iv->setValue(i, rec, (float) ((p->packet[(12+2*i)] << 8) + p->packet[(13+2*i)])/1);
@@ -680,7 +679,7 @@ class Communication : public CommQueue<> {
                     DBGPRINT(F("HW_VER is "));
                     DBGPRINTLN(String((p->packet[24] << 8) + p->packet[25]));
                 }
-                record_t<> *rec = q->iv->getRecordStruct(InverterDevInform_Simple);  // choose the record structure
+                rec = q->iv->getRecordStruct(InverterDevInform_Simple);  // choose the record structure
                 rec->ts = q->ts;
                 q->iv->setValue(1, rec, (uint32_t) ((p->packet[24] << 8) + p->packet[25])/1);
                 q->iv->miMultiParts +=4;
@@ -894,7 +893,7 @@ class Communication : public CommQueue<> {
                     statusMi = 8310;       //trick?
             }
 
-            uint16_t prntsts = statusMi == 3 ? 1 : statusMi;
+            uint16_t prntsts = (statusMi == 3) ? 1 : statusMi;
             bool stsok = true;
             if ( prntsts != rec->record[q->iv->getPosByChFld(0, FLD_EVT, rec)] ) { //sth.'s changed?
                 q->iv->alarmCnt = 1; // minimum...
@@ -1017,17 +1016,17 @@ class Communication : public CommQueue<> {
 
     private:
         States mState = States::RESET;
-        uint32_t *mTimestamp;
-        bool *mPrivacyMode, *mSerialDebug, *mPrintWholeTrace;
+        uint32_t *mTimestamp = nullptr;
+        bool *mPrivacyMode = nullptr, *mSerialDebug = nullptr, *mPrintWholeTrace = nullptr;
         TimeMonitor mWaitTime = TimeMonitor(0, true);  // start as expired (due to code in RESET state)
         std::array<frame_t, MAX_PAYLOAD_ENTRIES> mLocalBuf;
         bool mFirstTry = false;      // see, if we should do a second try
         bool mCompleteRetry = false; // remember if we did request a complete retransmission
         bool mIsRetransmit = false;  // we already had waited one complete cycle
-        uint8_t mMaxFrameId;
+        uint8_t mMaxFrameId = 0;
         uint8_t mFramesExpected = 12; // 0x8c was highest last frame for alarm data
         uint16_t mTimeout = 0;       // calculating that once should be ok
-        uint8_t mPayload[MAX_BUFFER];
+        std::array<uint8_t, MAX_BUFFER> mPayload;
         payloadListenerType mCbPayload = NULL;
         powerLimitAckListenerType mCbPwrAck = NULL;
         alarmListenerType mCbAlarm = NULL;
diff --git a/src/hm/Heuristic.h b/src/hm/Heuristic.h
index fa4512b50..2a36bc78b 100644
--- a/src/hm/Heuristic.h
+++ b/src/hm/Heuristic.h
@@ -157,7 +157,7 @@ class Heuristic {
                 DBGPRINTLN(String(iv->config->powerLevel));
         }
 
-        uint8_t getIvRetries(Inverter<> *iv) {
+        uint8_t getIvRetries(const Inverter<> *iv) const {
             if(iv->heuristics.rxSpeeds[0])
                 return RETRIES_VERYFAST_IV;
             if(iv->heuristics.rxSpeeds[1])
@@ -200,7 +200,7 @@ class Heuristic {
         }
 
     private:
-        bool isNewTxCh(HeuristicInv *ih) {
+        bool isNewTxCh(const HeuristicInv *ih) const {
             return ih->txRfChId != ih->lastBestTxChId;
         }
 
@@ -222,9 +222,6 @@ class Heuristic {
             }
             return 3; // standard
         }
-
-    private:
-        uint8_t mChList[5] = {03, 23, 40, 61, 75};
 };
 
 
diff --git a/src/hm/hmDefines.h b/src/hm/hmDefines.h
index 0b42aeae9..8fc4f71f1 100644
--- a/src/hm/hmDefines.h
+++ b/src/hm/hmDefines.h
@@ -76,7 +76,7 @@ enum {CMD_CALC = 0xffff};
 enum {CH0 = 0, CH1, CH2, CH3, CH4, CH5, CH6};
 
 enum {INV_TYPE_1CH = 0, INV_TYPE_2CH, INV_TYPE_4CH, INV_TYPE_6CH};
-enum {INV_RADIO_TYPE_NRF = 0, INV_RADIO_TYPE_CMT};
+enum {INV_RADIO_TYPE_UNKNOWN = 0, INV_RADIO_TYPE_NRF, INV_RADIO_TYPE_CMT};
 
 
 #define DURATION_ONEFRAME       50 // timeout parameter for each expected frame (ms)
diff --git a/src/hm/hmInverter.h b/src/hm/hmInverter.h
index b62e985ae..275fce2ca 100644
--- a/src/hm/hmInverter.h
+++ b/src/hm/hmInverter.h
@@ -81,12 +81,12 @@ enum class InverterStatus : uint8_t {
 
 template<class T=float>
 struct record_t {
-    byteAssign_t* assign;          // assignment of bytes in payload
-    uint8_t length;                // length of the assignment list
-    T *record;                     // data pointer
-    uint32_t ts;                   // timestamp of last received payload
-    uint8_t pyldLen;               // expected payload length for plausibility check
-    MqttSentStatus mqttSentStatus; // indicates the current MqTT sent status
+    byteAssign_t* assign = nullptr; // assignment of bytes in payload
+    uint8_t length = 0;             // length of the assignment list
+    T *record = nullptr;            // data pointer
+    uint32_t ts = 0;                // timestamp of last received payload
+    uint8_t pyldLen = 0;            // expected payload length for plausibility check
+    MqttSentStatus mqttSentStatus = MqttSentStatus:: NEW_DATA; // indicates the current MqTT sent status
 };
 
 struct alarm_t {
@@ -113,42 +113,42 @@ const calcFunc_t<T> calcFunctions[] = {
 template <class REC_TYP>
 class Inverter {
     public:
-        uint8_t       ivGen;             // generation of inverter (HM / MI)
-        uint8_t       ivRadioType;       // refers to used radio (nRF24 / CMT)
-        cfgIv_t       *config;           // stored settings
-        uint8_t       id;                // unique id
-        uint8_t       type;              // integer which refers to inverter type
-        uint16_t      alarmMesIndex;     // Last recorded Alarm Message Index
-        uint16_t      powerLimit[2];     // limit power output (multiplied by 10)
-        float         actPowerLimit;     // actual power limit
-        bool          powerLimitAck;     // acknowledged power limit (default: false)
-        uint8_t       devControlCmd;     // carries the requested cmd
-        serial_u      radioId;           // id converted to modbus
-        uint8_t       channels;          // number of PV channels (1-4)
-        record_t<REC_TYP> recordMeas;    // structure for measured values
-        record_t<REC_TYP> recordInfo;    // structure for info values
-        record_t<REC_TYP> recordHwInfo;  // structure for simple (hardware) info values
-        record_t<REC_TYP> recordConfig;  // structure for system config values
-        record_t<REC_TYP> recordAlarm;   // structure for alarm values
-        InverterStatus status;           // indicates the current inverter status
-        std::array<alarm_t, 10> lastAlarm; // holds last 10 alarms
-        uint8_t       rxOffset;          // holds the default channel offset between tx and rx channel (nRF only)
-        int8_t        rssi;              // RSSI
-        uint16_t      alarmCnt;          // counts the total number of occurred alarms
-        uint16_t      alarmLastId;       // lastId which was received
-        uint8_t       mCmd;              // holds the command to send
-        bool          mGotFragment;      // shows if inverter has sent at least one fragment
-        uint8_t       miMultiParts;      // helper info for MI multiframe msgs
-        uint8_t       outstandingFrames; // helper info to count difference between expected and received frames
-        uint8_t       curFrmCnt;         // count received frames in current loop
-        bool          mGotLastMsg;       // shows if inverter has already finished transmission cycle
-        bool          mIsSingleframeReq; // indicates this is a missing single frame request
-        Radio         *radio;            // pointer to associated radio class
-        statistics_t  radioStatistics;   // information about transmitted, failed, ... packets
-        HeuristicInv  heuristics;        // heuristic information / logic
-        uint8_t       curCmtFreq;        // current used CMT frequency, used to check if freq. was changed during runtime
-        bool          commEnabled;       // 'pause night communication' sets this field to false
-        uint32_t      tsMaxAcPower;      // holds the timestamp when the MaxAC power was seen
+        uint8_t       ivGen = IV_UNKNOWN;                   // generation of inverter (HM / MI)
+        uint8_t       ivRadioType = INV_RADIO_TYPE_UNKNOWN; // refers to used radio (nRF24 / CMT)
+        cfgIv_t       *config = nullptr;                    // stored settings
+        uint8_t       id = 0;                               // unique id
+        uint8_t       type = INV_TYPE_1CH;                  // integer which refers to inverter type
+        uint16_t      alarmMesIndex = 0;                    // Last recorded Alarm Message Index
+        uint16_t      powerLimit[2] = {0xffff, AbsolutNonPersistent}; // limit power output (multiplied by 10)
+        float         actPowerLimit = -1;                   // actual power limit
+        bool          powerLimitAck = false;                // acknowledged power limit
+        uint8_t       devControlCmd = InitDataState;        // carries the requested cmd
+        serial_u      radioId;                              // id converted to modbus
+        uint8_t       channels = 1;                         // number of PV channels (1-4)
+        record_t<REC_TYP> recordMeas;                       // structure for measured values
+        record_t<REC_TYP> recordInfo;                       // structure for info values
+        record_t<REC_TYP> recordHwInfo;                     // structure for simple (hardware) info values
+        record_t<REC_TYP> recordConfig;                     // structure for system config values
+        record_t<REC_TYP> recordAlarm;                      // structure for alarm values
+        InverterStatus status = InverterStatus::OFF;        // indicates the current inverter status
+        std::array<alarm_t, 10> lastAlarm;                  // holds last 10 alarms
+        uint8_t       rxOffset = 0;                         // holds the default channel offset between tx and rx channel (nRF only)
+        int8_t        rssi = 0;                             // RSSI
+        uint16_t      alarmCnt = 0;                         // counts the total number of occurred alarms
+        uint16_t      alarmLastId = 0;                      // lastId which was received
+        uint8_t       mCmd = InitDataState;                 // holds the command to send
+        bool          mGotFragment = false;                 // shows if inverter has sent at least one fragment
+        uint8_t       miMultiParts = 0;                     // helper info for MI multiframe msgs
+        uint8_t       outstandingFrames = 0;                // helper info to count difference between expected and received frames
+        uint8_t       curFrmCnt = 0;                        // count received frames in current loop
+        bool          mGotLastMsg = false;                  // shows if inverter has already finished transmission cycle
+        bool          mIsSingleframeReq = false;            // indicates this is a missing single frame request
+        Radio         *radio = nullptr;                     // pointer to associated radio class
+        statistics_t  radioStatistics;                      // information about transmitted, failed, ... packets
+        HeuristicInv  heuristics;                           // heuristic information / logic
+        uint8_t       curCmtFreq = 0;                       // current used CMT frequency, used to check if freq. was changed during runtime
+        uint32_t      tsMaxAcPower = 0;                     // holds the timestamp when the MaxAC power was seen
+        bool          commEnabled = true;                   // 'pause night communication' sets this field to false
 
         static uint32_t  *timestamp;     // system timestamp
         static cfgInst_t *generalConfig; // general inverter configuration from setup
@@ -156,29 +156,10 @@ class Inverter {
     public:
 
         Inverter() {
-            ivGen              = IV_HM;
-            powerLimit[0]      = 0xffff;               // 6553.5 W Limit -> unlimited
-            powerLimit[1]      = AbsolutNonPersistent; // default power limit setting
-            powerLimitAck      = false;
-            actPowerLimit      = 0xffff;               // init feedback from inverter to -1
-            mDevControlRequest = false;
-            devControlCmd      = InitDataState;
-            alarmMesIndex      = 0;
-            status             = InverterStatus::OFF;
-            alarmCnt           = 0;
-            alarmLastId        = 0;
-            rssi               = -127;
-            miMultiParts       = 0;
-            mGotLastMsg        = false;
-            mCmd               = InitDataState;
-            mIsSingleframeReq  = false;
-            radio              = NULL;
-            commEnabled        = true;
-            tsMaxAcPower       = 0;
-
             memset(&radioStatistics, 0, sizeof(statistics_t));
             memset(mOffYD, 0, sizeof(float) * 6);
             memset(mLastYD, 0, sizeof(float) * 6);
+            mGridProfile.fill(0);
         }
 
         void tickSend(std::function<void(uint8_t cmd, bool isDevControl)> cb) {
@@ -255,8 +236,8 @@ class Inverter {
 
         uint8_t getPosByChFld(uint8_t channel, uint8_t fieldId, record_t<> *rec) {
             DPRINTLN(DBG_VERBOSE, F("hmInverter.h:getPosByChFld"));
-            uint8_t pos = 0;
             if(NULL != rec) {
+                uint8_t pos = 0;
                 for(; pos < rec->length; pos++) {
                     if((rec->assign[pos].ch == channel) && (rec->assign[pos].fieldId == fieldId))
                         break;
@@ -303,7 +284,7 @@ class Inverter {
             return (InverterStatus::OFF != status);
         }
 
-        void addValue(uint8_t pos, uint8_t buf[], record_t<> *rec) {
+        void addValue(uint8_t pos, const uint8_t buf[], record_t<> *rec) {
             DPRINTLN(DBG_VERBOSE, F("hmInverter.h:addValue"));
             if(NULL != rec) {
                 uint8_t  ptr = rec->assign[pos].start;
@@ -387,8 +368,8 @@ class Inverter {
         }
 
         REC_TYP getChannelFieldValue(uint8_t channel, uint8_t fieldId, record_t<> *rec) {
-            uint8_t pos = 0;
             if(NULL != rec) {
+                uint8_t pos = 0;
                 for(; pos < rec->length; pos++) {
                     if((rec->assign[pos].ch == channel) && (rec->assign[pos].fieldId == fieldId))
                         break;
@@ -529,11 +510,11 @@ class Inverter {
                     if (INV_TYPE_1CH == type) {
                         if((IV_HM == ivGen) || (IV_MI == ivGen)) {
                             rec->length  = (uint8_t)(HM1CH_LIST_LEN);
-                            rec->assign  = (byteAssign_t *)hm1chAssignment;
+                            rec->assign  = reinterpret_cast<byteAssign_t*>(const_cast<byteAssign_t*>(hm1chAssignment));
                             rec->pyldLen = HM1CH_PAYLOAD_LEN;
                         } else if(IV_HMS == ivGen) {
                             rec->length  = (uint8_t)(HMS1CH_LIST_LEN);
-                            rec->assign  = (byteAssign_t *)hms1chAssignment;
+                            rec->assign  = reinterpret_cast<byteAssign_t*>(const_cast<byteAssign_t*>(hms1chAssignment));
                             rec->pyldLen = HMS1CH_PAYLOAD_LEN;
                         }
                         channels = 1;
@@ -541,11 +522,11 @@ class Inverter {
                     else if (INV_TYPE_2CH == type) {
                         if((IV_HM == ivGen) || (IV_MI == ivGen)) {
                             rec->length  = (uint8_t)(HM2CH_LIST_LEN);
-                            rec->assign  = (byteAssign_t *)hm2chAssignment;
+                            rec->assign  = reinterpret_cast<byteAssign_t*>(const_cast<byteAssign_t*>(hm2chAssignment));
                             rec->pyldLen = HM2CH_PAYLOAD_LEN;
                         } else if(IV_HMS == ivGen) {
                             rec->length  = (uint8_t)(HMS2CH_LIST_LEN);
-                            rec->assign  = (byteAssign_t *)hms2chAssignment;
+                            rec->assign  = reinterpret_cast<byteAssign_t*>(const_cast<byteAssign_t*>(hms2chAssignment));
                             rec->pyldLen = HMS2CH_PAYLOAD_LEN;
                         }
                         channels = 2;
@@ -553,18 +534,18 @@ class Inverter {
                     else if (INV_TYPE_4CH == type) {
                         if((IV_HM == ivGen) || (IV_MI == ivGen)) {
                             rec->length  = (uint8_t)(HM4CH_LIST_LEN);
-                            rec->assign  = (byteAssign_t *)hm4chAssignment;
+                            rec->assign  = reinterpret_cast<byteAssign_t*>(const_cast<byteAssign_t*>(hm4chAssignment));
                             rec->pyldLen = HM4CH_PAYLOAD_LEN;
                         } else if(IV_HMS == ivGen) {
                             rec->length  = (uint8_t)(HMS4CH_LIST_LEN);
-                            rec->assign  = (byteAssign_t *)hms4chAssignment;
+                            rec->assign  = reinterpret_cast<byteAssign_t*>(const_cast<byteAssign_t*>(hms4chAssignment));
                             rec->pyldLen = HMS4CH_PAYLOAD_LEN;
                         }
                         channels = 4;
                     }
                     else if (INV_TYPE_6CH == type) {
                         rec->length  = (uint8_t)(HMT6CH_LIST_LEN);
-                        rec->assign  = (byteAssign_t *)hmt6chAssignment;
+                        rec->assign  = reinterpret_cast<byteAssign_t*>(const_cast<byteAssign_t*>(hmt6chAssignment));
                         rec->pyldLen = HMT6CH_PAYLOAD_LEN;
                         channels = 6;
                     }
@@ -577,22 +558,22 @@ class Inverter {
                     break;
                 case InverterDevInform_All:
                     rec->length  = (uint8_t)(HMINFO_LIST_LEN);
-                    rec->assign  = (byteAssign_t *)InfoAssignment;
+                    rec->assign  = reinterpret_cast<byteAssign_t*>(const_cast<byteAssign_t*>(InfoAssignment));
                     rec->pyldLen = HMINFO_PAYLOAD_LEN;
                     break;
                 case InverterDevInform_Simple:
                     rec->length  = (uint8_t)(HMSIMPLE_INFO_LIST_LEN);
-                    rec->assign  = (byteAssign_t *)SimpleInfoAssignment;
+                    rec->assign  = reinterpret_cast<byteAssign_t*>(const_cast<byteAssign_t*>(SimpleInfoAssignment));
                     rec->pyldLen = HMSIMPLE_INFO_PAYLOAD_LEN;
                     break;
                 case SystemConfigPara:
                     rec->length  = (uint8_t)(HMSYSTEM_LIST_LEN);
-                    rec->assign  = (byteAssign_t *)SystemConfigParaAssignment;
+                    rec->assign  = reinterpret_cast<byteAssign_t*>(const_cast<byteAssign_t*>(SystemConfigParaAssignment));
                     rec->pyldLen = HMSYSTEM_PAYLOAD_LEN;
                     break;
                 case AlarmData:
                     rec->length  = (uint8_t)(HMALARMDATA_LIST_LEN);
-                    rec->assign  = (byteAssign_t *)AlarmDataAssignment;
+                    rec->assign  = reinterpret_cast<byteAssign_t*>(const_cast<byteAssign_t*>(AlarmDataAssignment));
                     rec->pyldLen = HMALARMDATA_PAYLOAD_LEN;
                     break;
                 default:
@@ -616,7 +597,7 @@ class Inverter {
             memset(mLastYD, 0, sizeof(float) * 6);
         }
 
-        bool parseGetLossRate(uint8_t pyld[], uint8_t len) {
+        bool parseGetLossRate(const uint8_t pyld[], uint8_t len) {
             if (len == HMGETLOSSRATE_PAYLOAD_LEN) {
                 uint16_t rxCnt = (pyld[0] << 8) + pyld[1];
                 uint16_t txCnt = (pyld[2] << 8) + pyld[3];
@@ -815,7 +796,7 @@ class Inverter {
 
         void addGridProfile(uint8_t buf[], uint8_t length) {
             mGridLen = (length > MAX_GRID_LENGTH) ? MAX_GRID_LENGTH : length;
-            std::copy(buf, &buf[mGridLen], mGridProfile);
+            std::copy(buf, &buf[mGridLen], mGridProfile.data());
         }
 
         String getGridProfile(void) {
@@ -847,9 +828,9 @@ class Inverter {
 
     private:
         float mOffYD[6], mLastYD[6];
-        bool mDevControlRequest; // true if change needed
+        bool mDevControlRequest = false; // true if change needed
         uint8_t mGridLen = 0;
-        uint8_t mGridProfile[MAX_GRID_LENGTH];
+        std::array<uint8_t, MAX_GRID_LENGTH> mGridProfile;
         uint8_t mAlarmNxtWrPos = 0; // indicates the position in array (rolling buffer)
 
     public:
diff --git a/src/hm/hmRadio.h b/src/hm/hmRadio.h
index ca96a3330..aef4f49d1 100644
--- a/src/hm/hmRadio.h
+++ b/src/hm/hmRadio.h
@@ -52,7 +52,7 @@ class HmRadio : public Radio {
             mPrintWholeTrace = printWholeTrace;
 
             generateDtuSn();
-            DTU_RADIO_ID = ((uint64_t)(((mDtuSn >> 24) & 0xFF) | ((mDtuSn >> 8) & 0xFF00) | ((mDtuSn << 8) & 0xFF0000) | ((mDtuSn << 24) & 0xFF000000)) << 8) | 0x01;
+            mDtuRadioId = ((uint64_t)(((mDtuSn >> 24) & 0xFF) | ((mDtuSn >> 8) & 0xFF00) | ((mDtuSn << 8) & 0xFF0000) | ((mDtuSn << 24) & 0xFF000000)) << 8) | 0x01;
 
             #ifdef ESP32
                 #if defined(CONFIG_IDF_TARGET_ESP32S3) && defined(SPI_HAL)
@@ -85,7 +85,7 @@ class HmRadio : public Radio {
             mNrf24->enableDynamicPayloads();
             mNrf24->setCRCLength(RF24_CRC_16);
             mNrf24->setAddressWidth(5);
-            mNrf24->openReadingPipe(1, reinterpret_cast<uint8_t*>(&DTU_RADIO_ID));
+            mNrf24->openReadingPipe(1, reinterpret_cast<uint8_t*>(&mDtuRadioId));
             mNrf24->maskIRQ(false, false, false); // enable all receiving interrupts
             mNrf24->setPALevel(1); // low is default
 
@@ -99,7 +99,7 @@ class HmRadio : public Radio {
         }
 
         // returns true if communication is active
-        bool loop(void) {
+        bool loop(void) override {
             if (!mIrqRcvd && !mNRFisInRX)
                 return false; // first quick check => nothing to do at all here
 
@@ -198,11 +198,11 @@ class HmRadio : public Radio {
             return false;
         }
 
-        bool isChipConnected(void) const {
+        bool isChipConnected(void) const override {
             return mNrf24->isChipConnected();
         }
 
-        void sendControlPacket(Inverter<> *iv, uint8_t cmd, uint16_t *data, bool isRetransmit) {
+        void sendControlPacket(Inverter<> *iv, uint8_t cmd, uint16_t *data, bool isRetransmit) override {
             DPRINT_IVID(DBG_INFO, iv->id);
             DBGPRINT(F("sendControlPacket cmd: "));
             DBGHEXLN(cmd);
@@ -423,15 +423,15 @@ class HmRadio : public Radio {
             mNRFisInRX = false;
         }
 
-        uint64_t getIvId(Inverter<> *iv) const {
+        uint64_t getIvId(Inverter<> *iv) const override {
             return iv->radioId.u64;
         }
 
-        uint8_t getIvGen(Inverter<> *iv) const {
+        uint8_t getIvGen(Inverter<> *iv) const override {
             return iv->ivGen;
         }
 
-        inline bool checkIvSerial(uint8_t buf[], Inverter<> *iv) {
+        inline bool checkIvSerial(const uint8_t buf[], Inverter<> *iv) {
             for(uint8_t i = 1; i < 5; i++) {
                 if(buf[i] != iv->radioId.b[i])
                     return false;
@@ -439,14 +439,14 @@ class HmRadio : public Radio {
             return true;
         }
 
-        uint64_t DTU_RADIO_ID;
-        uint8_t mRfChLst[RF_CHANNELS] = {03, 23, 40, 61, 75}; // channel List:2403, 2423, 2440, 2461, 2475MHz
+        uint64_t mDtuRadioId = 0ULL;
+        const uint8_t mRfChLst[RF_CHANNELS] = {03, 23, 40, 61, 75}; // channel List:2403, 2423, 2440, 2461, 2475MHz
         uint8_t mTxChIdx = 0;
         uint8_t mRxChIdx = 0;
-        uint8_t tempRxChIdx = mRxChIdx;
+        uint8_t tempRxChIdx = 0;
         bool    mGotLastMsg = false;
-        uint32_t mMillis;
-        bool tx_ok, tx_fail, rx_ready = false;
+        uint32_t mMillis = 0;
+        bool tx_ok = false, tx_fail = false, rx_ready = false;
         unsigned long mTimeslotStart = 0;
         unsigned long mLastIrqTime = 0;
         bool mNRFloopChannels = false;
@@ -454,7 +454,6 @@ class HmRadio : public Radio {
         bool isRxInit = true;
         bool mRxPendular = false;
         uint32_t innerLoopTimeout = DURATION_LISTEN_MIN;
-        //uint8_t mTxSetupTime = 0;
         uint8_t mTxRetries = 15;                            // memorize last setting for mNrf24->setRetries(3, 15);
 
         std::unique_ptr<SPIClass> mSpi;
diff --git a/src/hm/hmSystem.h b/src/hm/hmSystem.h
index aa2910e54..0266a9485 100644
--- a/src/hm/hmSystem.h
+++ b/src/hm/hmSystem.h
@@ -98,35 +98,33 @@ class HmSystem {
             #ifdef DYNAMIC_OFFSET
             iv->rxOffset = (iv->ivGen == IV_HM) ? 13 : 12; // effective 3 (or 2), but can easily be recognized as default setting
             #else
-            iv->rxOffset = ((iv->ivGen == IV_HM) && (iv->type == INV_TYPE_4CH)) ? 3 : 2;
+            //iv->rxOffset = ((iv->ivGen == IV_HM) && (iv->type == INV_TYPE_4CH)) ? 3 : 2;
             iv->rxOffset = (iv->ivGen == IV_HM) ? 3 : 2;
             #endif
 
             cb(iv);
         }
 
-        INVERTERTYPE *findInverter(uint8_t buf[]) {
-            DPRINTLN(DBG_VERBOSE, F("hmSystem.h:findInverter"));
-            INVERTERTYPE *p;
+        INVERTERTYPE *findInverter(const uint8_t buf[]) {
             for(uint8_t i = 0; i < MAX_INVERTER; i++) {
-                p = &mInverter[i];
+                INVERTERTYPE *p = &mInverter[i];
                 if((p->config->serial.b[3] == buf[0])
                     && (p->config->serial.b[2] == buf[1])
                     && (p->config->serial.b[1] == buf[2])
                     && (p->config->serial.b[0] == buf[3]))
                     return p;
             }
-            return NULL;
+            return nullptr;
         }
 
         INVERTERTYPE *getInverterByPos(uint8_t pos, bool check = true) {
             DPRINTLN(DBG_VERBOSE, F("hmSystem.h:getInverterByPos"));
             if(pos >= MAX_INVERTER)
-                return NULL;
+                return nullptr;
             else if((mInverter[pos].config->serial.u64 != 0ULL) || (false == check))
                 return &mInverter[pos];
             else
-                return NULL;
+                return nullptr;
         }
 
         uint8_t getNumInverters(void) {
diff --git a/src/hm/nrfHal.h b/src/hm/nrfHal.h
index 0532a5240..b9265626c 100644
--- a/src/hm/nrfHal.h
+++ b/src/hm/nrfHal.h
@@ -142,7 +142,7 @@ class nrfHal: public RF24_hal, public SpiPatcherHandle {
         }
 
         uint8_t read(uint8_t cmd, uint8_t* buf, uint8_t len) override {
-            uint8_t data[NRF_MAX_TRANSFER_SZ];
+            uint8_t data[NRF_MAX_TRANSFER_SZ + 1];
             data[0] = cmd;
             if(len > NRF_MAX_TRANSFER_SZ)
                 len = NRF_MAX_TRANSFER_SZ;
diff --git a/src/hm/radio.h b/src/hm/radio.h
index 7bbb42bc8..db694b545 100644
--- a/src/hm/radio.h
+++ b/src/hm/radio.h
@@ -11,6 +11,7 @@
 #define ALL_FRAMES          0x80
 #define SINGLE_FRAME        0x81
 
+#include <atomic>
 #include "../utils/dbg.h"
 #include "../utils/crc.h"
 #include "../utils/timemonitor.h"
@@ -119,9 +120,8 @@ class Radio {
             #endif
 
             mDtuSn = 0;
-            uint8_t t;
             for(int i = 0; i < (7 << 2); i += 4) {
-                t = (chipID >> i) & 0x0f;
+                uint8_t t = (chipID >> i) & 0x0f;
                 if(t > 0x09)
                     t -= 6;
                 mDtuSn |= (t << i);
@@ -132,8 +132,8 @@ class Radio {
 
 
         uint32_t mDtuSn;
-        volatile bool mIrqRcvd;
-        bool *mSerialDebug, *mPrivacyMode, *mPrintWholeTrace;
+        std::atomic<bool> mIrqRcvd;
+        bool *mSerialDebug = nullptr, *mPrivacyMode = nullptr, *mPrintWholeTrace = nullptr;
         uint8_t mTxBuf[MAX_RF_PAYLOAD_SIZE];
 };
 
diff --git a/src/hms/cmt2300a.h b/src/hms/cmt2300a.h
index e6456f5bf..23911b157 100644
--- a/src/hms/cmt2300a.h
+++ b/src/hms/cmt2300a.h
@@ -529,7 +529,8 @@ class Cmt2300a {
             return false;
         }
 
-        inline bool switchDtuFreq(const uint32_t freqKhz) {
+        // maybe used in future
+        /*inline bool switchDtuFreq(const uint32_t freqKhz) {
             uint8_t toCh = freq2Chan(freqKhz);
             if(0xff == toCh)
                 return false;
@@ -537,7 +538,7 @@ class Cmt2300a {
             switchChannel(toCh);
 
             return true;
-        }
+        }*/
 
         inline uint8_t getChipStatus(void) {
             return mSpi.readReg(CMT2300A_CUS_MODE_STA) & CMT2300A_MASK_CHIP_MODE_STA;
@@ -549,11 +550,11 @@ class Cmt2300a {
         #else
         esp32_3wSpi mSpi;
         #endif
-        uint8_t mCnt;
-        bool mTxPending;
-        bool mInRxMode;
-        uint8_t mCusIntFlag;
-        uint8_t mRqstCh, mCurCh;
+        uint8_t mCnt = 0;
+        bool mTxPending = false;
+        bool mInRxMode = false;
+        uint8_t mCusIntFlag = 0;
+        uint8_t mRqstCh = 0, mCurCh = 0;
         RegionCfg mRegionCfg = RegionCfg::EUROPE;
 };
 
diff --git a/src/hms/cmtHal.h b/src/hms/cmtHal.h
index 768b8da5a..a4bec5870 100644
--- a/src/hms/cmtHal.h
+++ b/src/hms/cmtHal.h
@@ -89,7 +89,7 @@ class cmtHal : public SpiPatcherHandle {
         }
 
         uint8_t readReg(uint8_t addr) {
-            uint8_t data;
+            uint8_t data = 0;
 
             request_spi();
 
diff --git a/src/hms/esp32_3wSpi.h b/src/hms/esp32_3wSpi.h
index c562671a9..a0366b238 100644
--- a/src/hms/esp32_3wSpi.h
+++ b/src/hms/esp32_3wSpi.h
@@ -10,6 +10,7 @@
 #if defined(ESP32)
 #include "driver/spi_master.h"
 #include "esp_rom_gpio.h" // for esp_rom_gpio_connect_out_signal
+#include "../config/config.h"
 
 #define SPI_CLK     1 * 1000 * 1000 // 1MHz
 
@@ -104,7 +105,7 @@ class esp32_3wSpi {
             if(!mInitialized)
                 return 0;
 
-            uint8_t rx_data;
+            uint8_t rx_data = 0;
             spi_transaction_t t = {
                 .cmd = 0,
                 .addr = (uint64_t)(~addr),
@@ -121,7 +122,7 @@ class esp32_3wSpi {
             return rx_data;
         }
 
-        void writeFifo(uint8_t buf[], uint8_t len) {
+        void writeFifo(const uint8_t buf[], uint8_t len) {
             if(!mInitialized)
                 return;
             uint8_t tx_data;
@@ -144,7 +145,7 @@ class esp32_3wSpi {
         void readFifo(uint8_t buf[], uint8_t *len, uint8_t maxlen) {
             if(!mInitialized)
                 return;
-            uint8_t rx_data;
+            uint8_t rx_data = 0;
 
             spi_transaction_t t = {
                 .length = 8,
diff --git a/src/hms/hmsRadio.h b/src/hms/hmsRadio.h
index 0fa1b6ab1..66e312d7b 100644
--- a/src/hms/hmsRadio.h
+++ b/src/hms/hmsRadio.h
@@ -15,10 +15,6 @@ template<uint32_t DTU_SN = 0x81001765>
 class CmtRadio : public Radio {
     typedef Cmt2300a CmtType;
     public:
-        CmtRadio() {
-            mDtuSn = DTU_SN;
-        }
-
         void setup(bool *serialDebug, bool *privacyMode, bool *printWholeTrace, uint8_t pinSclk, uint8_t pinSdio, uint8_t pinCsb, uint8_t pinFcsb, uint8_t region = 0, bool genDtuSn = true) {
             mCmt.setup(pinSclk, pinSdio, pinCsb, pinFcsb);
             reset(genDtuSn, static_cast<RegionCfg>(region));
@@ -27,7 +23,7 @@ class CmtRadio : public Radio {
             mPrintWholeTrace = printWholeTrace;
         }
 
-        bool loop() {
+        bool loop() override {
             mCmt.loop();
             if((!mIrqRcvd) && (!mRqstGetRx))
                 return false;
@@ -39,11 +35,11 @@ class CmtRadio : public Radio {
             return false;
         }
 
-        bool isChipConnected(void) const {
+        bool isChipConnected(void) const override {
             return mCmtAvail;
         }
 
-        void sendControlPacket(Inverter<> *iv, uint8_t cmd, uint16_t *data, bool isRetransmit) {
+        void sendControlPacket(Inverter<> *iv, uint8_t cmd, uint16_t *data, bool isRetransmit) override {
             DPRINT(DBG_INFO, F("sendControlPacket cmd: "));
             DBGHEXLN(cmd);
             initPacket(iv->radioId.u64, TX_REQ_DEVCONTROL, SINGLE_FRAME);
@@ -61,14 +57,14 @@ class CmtRadio : public Radio {
             sendPacket(iv, cnt, isRetransmit);
         }
 
-        bool switchFrequency(Inverter<> *iv, uint32_t fromkHz, uint32_t tokHz) {
+        bool switchFrequency(Inverter<> *iv, uint32_t fromkHz, uint32_t tokHz) override {
             uint8_t fromCh = mCmt.freq2Chan(fromkHz);
             uint8_t toCh = mCmt.freq2Chan(tokHz);
 
             return switchFrequencyCh(iv, fromCh, toCh);
         }
 
-        bool switchFrequencyCh(Inverter<> *iv, uint8_t fromCh, uint8_t toCh) {
+        bool switchFrequencyCh(Inverter<> *iv, uint8_t fromCh, uint8_t toCh) override {
             if((0xff == fromCh) || (0xff == toCh))
                 return false;
 
@@ -92,7 +88,7 @@ class CmtRadio : public Radio {
 
     private:
 
-        void sendPacket(Inverter<> *iv, uint8_t len, bool isRetransmit, bool appendCrc16=true) {
+        void sendPacket(Inverter<> *iv, uint8_t len, bool isRetransmit, bool appendCrc16=true) override {
             // inverters have maybe different settings regarding frequency
             if(mCmt.getCurrentChannel() != iv->config->frequency)
                 mCmt.switchChannel(iv->config->frequency);
@@ -129,11 +125,11 @@ class CmtRadio : public Radio {
             iv->mDtuTxCnt++;
         }
 
-        uint64_t getIvId(Inverter<> *iv) const {
+        uint64_t getIvId(Inverter<> *iv) const override {
             return iv->radioId.u64;
         }
 
-        uint8_t getIvGen(Inverter<> *iv) const {
+        uint8_t getIvGen(Inverter<> *iv) const override {
             return iv->ivGen;
         }
 
@@ -180,6 +176,7 @@ class CmtRadio : public Radio {
             p.millis = millis() - mMillis;
             if(CmtStatus::SUCCESS == mCmt.getRx(p.packet, &p.len, 28, &p.rssi)) {
                 mSwitchCycle = 0;
+                p.ch = 0; // not used for CMT inverters
                 mBufCtrl.push(p);
             }
 
@@ -187,14 +184,12 @@ class CmtRadio : public Radio {
                 setExpectedFrames(p.packet[9] - ALL_FRAMES);
                 mRadioWaitTime.startTimeMonitor(DURATION_PAUSE_LASTFR); // let the inverter first get back to rx mode?
             }
-            // optionally instead:
-            //    mRadioWaitTime.stopTimeMonitor(); // we got everything we expected and can exit rx mode...
         }
 
         CmtType mCmt;
         bool mCmtAvail = false;
         bool mRqstGetRx = false;
-        uint32_t mMillis;
+        uint32_t mMillis = 0;
         uint8_t mSwitchCycle = 0;
 };
 
diff --git a/src/plugins/Display/Display.h b/src/plugins/Display/Display.h
index 862e452b4..c59a56b62 100644
--- a/src/plugins/Display/Display.h
+++ b/src/plugins/Display/Display.h
@@ -192,15 +192,14 @@ class Display {
             if ((mCfg->screenSaver == 2) && (mCfg->pirPin != DEF_PIN_OFF)) {
     #if defined(ESP8266)
                 if (mCfg->pirPin == A0)
-                    return((analogRead(A0) >= 512));
+                    return (analogRead(A0) >= 512);
                 else
-                    return(digitalRead(mCfg->pirPin));
+                    return digitalRead(mCfg->pirPin);
     #elif defined(ESP32)
-                return(digitalRead(mCfg->pirPin));
+                return digitalRead(mCfg->pirPin);
     #endif
-            }
-            else
-                return(false);
+            } else
+                return false;
         }
 
         // approximate RSSI in dB by invQuality levels from heuristic function (very unscientific but better than nothing :-) )
diff --git a/src/plugins/Display/Display_Mono.h b/src/plugins/Display/Display_Mono.h
index 2c1fc9354..e855eeb9a 100644
--- a/src/plugins/Display/Display_Mono.h
+++ b/src/plugins/Display/Display_Mono.h
@@ -24,8 +24,6 @@
 
 class DisplayMono {
     public:
-        DisplayMono() {};
-
         virtual void init(DisplayData *displayData) = 0;
         virtual void config(display_t *cfg) = 0;
         virtual void disp(void) = 0;
@@ -289,11 +287,11 @@ class DisplayMono {
         DispSwitchState mDispSwitchState = DispSwitchState::TEXT;
 
         uint16_t mDispWidth;
-        uint8_t mExtra;
+        uint8_t mExtra = 0;
         int8_t  mPixelshift=0;
         char mFmtText[DISP_FMT_TEXT_LEN];
-        uint8_t mLineXOffsets[5] = {};
-        uint8_t mLineYOffsets[5] = {};
+        uint8_t mLineXOffsets[5] = {0, 0, 0, 0, 0};
+        uint8_t mLineYOffsets[5] = {0, 0, 0, 0, 0};
 
         uint8_t mPgWidth = 0;
 
@@ -308,8 +306,8 @@ class DisplayMono {
         uint32_t mPgLastTime = 0;
         PowerGraphState mPgState = PowerGraphState::NO_TIME_SYNC;
 
-        uint16_t mDispHeight;
-        uint8_t mLuminance;
+        uint16_t mDispHeight = 0;
+        uint8_t mLuminance = 0;
 
         TimeMonitor mDisplayTime = TimeMonitor(1000 * DISP_DEFAULT_TIMEOUT, true);
         TimeMonitor mDispSwitchTime = TimeMonitor();
diff --git a/src/plugins/history.h b/src/plugins/history.h
index 7a9382847..7e4156758 100644
--- a/src/plugins/history.h
+++ b/src/plugins/history.h
@@ -24,23 +24,15 @@ template<class HMSYSTEM>
 class HistoryData {
     private:
         struct storage_t {
-            uint16_t refreshCycle;
-            uint16_t loopCnt;
-            uint16_t listIdx; // index for next Element to write into WattArr
-            uint16_t dispIdx; // index for 1st Element to display from WattArr
-            bool wrapped;
+            uint16_t refreshCycle = 0;
+            uint16_t loopCnt = 0;
+            uint16_t listIdx = 0; // index for next Element to write into WattArr
+            uint16_t dispIdx = 0; // index for 1st Element to display from WattArr
+            bool wrapped = false;
             // ring buffer for watt history
             std::array<uint16_t, (HISTORY_DATA_ARR_LENGTH + 1)> data;
 
-            void reset() {
-                loopCnt = 0;
-                listIdx = 0;
-                dispIdx = 0;
-                wrapped = false;
-                for(uint16_t i = 0; i < (HISTORY_DATA_ARR_LENGTH + 1); i++) {
-                    data[i] = 0;
-                }
-            }
+            storage_t() { data.fill(0); }
         };
 
     public:
@@ -50,9 +42,7 @@ class HistoryData {
             mConfig = config;
             mTs = ts;
 
-            mCurPwr.reset();
             mCurPwr.refreshCycle = mConfig->inst.sendInterval;
-            //mYieldDay.reset();
             //mYieldDay.refreshCycle = 60;
         }
 
@@ -113,14 +103,13 @@ class HistoryData {
         }
 
     private:
-        IApp *mApp;
-        HMSYSTEM *mSys;
-        settings *mSettings;
-        settings_t *mConfig;
-        uint32_t *mTs;
+        IApp *mApp = nullptr;
+        HMSYSTEM *mSys = nullptr;
+        settings *mSettings = nullptr;
+        settings_t *mConfig = nullptr;
+        uint32_t *mTs = nullptr;
 
         storage_t mCurPwr;
-        //storage_t mYieldDay;
         bool mDayStored = false;
         uint16_t mMaximumDay = 0;
 };
diff --git a/src/publisher/pubMqtt.h b/src/publisher/pubMqtt.h
index 865c76b5a..7799b6d27 100644
--- a/src/publisher/pubMqtt.h
+++ b/src/publisher/pubMqtt.h
@@ -15,6 +15,7 @@
     #include <WiFi.h>
 #endif
 
+#include <array>
 #include "../utils/dbg.h"
 #include "../config/config.h"
 #include <espMqttClient.h>
@@ -38,12 +39,15 @@ template<class HMSYSTEM>
 class PubMqtt {
     public:
         PubMqtt() {
-            mRxCnt = 0;
-            mTxCnt = 0;
-            mSubscriptionCb = NULL;
-            memset(mLastIvState, (uint8_t)InverterStatus::OFF, MAX_NUM_INVERTERS);
-            memset(mIvLastRTRpub, 0, MAX_NUM_INVERTERS * 4);
-            mLastAnyAvail = false;
+            mLastIvState.fill(InverterStatus::OFF);
+            mIvLastRTRpub.fill(0);
+
+            mVal.fill(0);
+            mTopic.fill(0);
+            mSubTopic.fill(0);
+            mClientId.fill(0);
+            mLwtTopic.fill(0);
+            mSendAlarm.fill(false);
         }
 
         ~PubMqtt() { }
@@ -63,16 +67,16 @@ class PubMqtt {
             });
             mDiscovery.running = false;
 
-            snprintf(mLwtTopic, MQTT_TOPIC_LEN + 5, "%s/mqtt", mCfgMqtt->topic);
+            snprintf(mLwtTopic.data(), mLwtTopic.size(), "%s/mqtt", mCfgMqtt->topic);
 
             if((strlen(mCfgMqtt->user) > 0) && (strlen(mCfgMqtt->pwd) > 0))
                 mClient.setCredentials(mCfgMqtt->user, mCfgMqtt->pwd);
 
             if(strlen(mCfgMqtt->clientId) > 0)
-                snprintf(mClientId, 23, "%s", mCfgMqtt->clientId);
+                snprintf(mClientId.data(), mClientId.size(), "%s", mCfgMqtt->clientId);
             else {
-                snprintf(mClientId, 23, "%s-", mDevName);
-                uint8_t pos = strlen(mClientId);
+                snprintf(mClientId.data(), mClientId.size(), "%s-", mDevName);
+                uint8_t pos = strlen(mClientId.data());
                 mClientId[pos++] = WiFi.macAddress().substring( 9, 10).c_str()[0];
                 mClientId[pos++] = WiFi.macAddress().substring(10, 11).c_str()[0];
                 mClientId[pos++] = WiFi.macAddress().substring(12, 13).c_str()[0];
@@ -82,9 +86,9 @@ class PubMqtt {
                 mClientId[pos++] = '\0';
             }
 
-            mClient.setClientId(mClientId);
+            mClient.setClientId(mClientId.data());
             mClient.setServer(mCfgMqtt->broker, mCfgMqtt->port);
-            mClient.setWill(mLwtTopic, QOS_0, true, mqttStr[MQTT_STR_LWT_NOT_CONN]);
+            mClient.setWill(mLwtTopic.data(), QOS_0, true, mqttStr[MQTT_STR_LWT_NOT_CONN]);
             mClient.onConnect(std::bind(&PubMqtt::onConnect, this, std::placeholders::_1));
             mClient.onDisconnect(std::bind(&PubMqtt::onDisconnect, this, std::placeholders::_1));
             mClient.onMessage(std::bind(&PubMqtt::onMessage, this, std::placeholders::_1, std::placeholders::_2, std::placeholders::_3, std::placeholders::_4, std::placeholders::_5, std::placeholders::_6));
@@ -125,8 +129,8 @@ class PubMqtt {
         }
 
         void tickerMinute() {
-            snprintf(mVal, 40, "%d", (*mUptime));
-            publish(subtopics[MQTT_UPTIME], mVal);
+            snprintf(mVal.data(), mVal.size(), "%u", (*mUptime));
+            publish(subtopics[MQTT_UPTIME], mVal.data());
             publish(subtopics[MQTT_RSSI], String(WiFi.RSSI()).c_str());
             publish(subtopics[MQTT_FREE_HEAP], String(ESP.getFreeHeap()).c_str());
             #ifndef ESP32
@@ -143,18 +147,17 @@ class PubMqtt {
             publish(subtopics[MQTT_COMM_START], String(sunrise + offsM).c_str(), true);
             publish(subtopics[MQTT_COMM_STOP], String(sunset + offsE).c_str(), true);
 
-            Inverter<> *iv;
             for(uint8_t i = 0; i < MAX_NUM_INVERTERS; i++) {
-                iv = mSys->getInverterByPos(i);
+                Inverter<> *iv = mSys->getInverterByPos(i);
                 if(NULL == iv)
                     continue;
 
-                snprintf(mSubTopic, 32 + MAX_NAME_LENGTH, "%s/dis_night_comm", iv->config->name);
-                publish(mSubTopic, ((iv->commEnabled) ? dict[STR_TRUE] : dict[STR_FALSE]), true);
+                snprintf(mSubTopic.data(), mSubTopic.size(), "%s/dis_night_comm", iv->config->name);
+                publish(mSubTopic.data(), ((iv->commEnabled) ? dict[STR_TRUE] : dict[STR_FALSE]), true);
             }
 
-            snprintf(mSubTopic, 32 + MAX_NAME_LENGTH, "comm_disabled");
-            publish(mSubTopic, (((*mUtcTimestamp > (sunset + offsE)) || (*mUtcTimestamp < (sunrise + offsM))) ? dict[STR_TRUE] : dict[STR_FALSE]), true);
+            snprintf(mSubTopic.data(), mSubTopic.size(), "comm_disabled");
+            publish(mSubTopic.data(), (((*mUtcTimestamp > (sunset + offsE)) || (*mUtcTimestamp < (sunrise + offsM))) ? dict[STR_TRUE] : dict[STR_FALSE]), true);
 
             return true;
         }
@@ -176,9 +179,9 @@ class PubMqtt {
 
         void tickerMidnight() {
             // set Total YieldDay to zero
-            snprintf(mSubTopic, 32 + MAX_NAME_LENGTH, "total/%s", fields[FLD_YD]);
-            snprintf(mVal, 2, "0");
-            publish(mSubTopic, mVal, true);
+            snprintf(mSubTopic.data(), mSubTopic.size(), "total/%s", fields[FLD_YD]);
+            snprintf(mVal.data(), mVal.size(), "0");
+            publish(mSubTopic.data(), mVal.data(), true);
         }
 
         void payloadEventListener(uint8_t cmd, Inverter<> *iv) {
@@ -197,11 +200,11 @@ class PubMqtt {
                 return;
 
             if(addTopic)
-                snprintf(mTopic, MQTT_TOPIC_LEN + 32 + MAX_NAME_LENGTH + 1, "%s/%s", mCfgMqtt->topic, subTopic);
+                snprintf(mTopic.data(), mTopic.size(), "%s/%s", mCfgMqtt->topic, subTopic);
             else
-                snprintf(mTopic, MQTT_TOPIC_LEN + 32 + MAX_NAME_LENGTH + 1, "%s", subTopic);
+                snprintf(mTopic.data(), mTopic.size(), "%s", subTopic);
 
-            mClient.publish(mTopic, qos, retained, payload);
+            mClient.publish(mTopic.data(), qos, retained, payload);
             yield();
             mTxCnt++;
         }
@@ -238,8 +241,8 @@ class PubMqtt {
 
         void setPowerLimitAck(Inverter<> *iv) {
             if (NULL != iv) {
-                snprintf(mSubTopic, 32 + MAX_NAME_LENGTH, "%s/%s", iv->config->name, subtopics[MQTT_ACK_PWR_LMT]);
-                publish(mSubTopic, "true", true, true, QOS_2);
+                snprintf(mSubTopic.data(), mSubTopic.size(), "%s/%s", iv->config->name, subtopics[MQTT_ACK_PWR_LMT]);
+                publish(mSubTopic.data(), "true", true, true, QOS_2);
             }
         }
 
@@ -255,15 +258,15 @@ class PubMqtt {
             publish(subtopics[MQTT_IP_ADDR], WiFi.localIP().toString().c_str(), true);
             #endif
             tickerMinute();
-            publish(mLwtTopic, mqttStr[MQTT_STR_LWT_CONN], true, false);
+            publish(mLwtTopic.data(), mqttStr[MQTT_STR_LWT_CONN], true, false);
 
             for(uint8_t i = 0; i < MAX_NUM_INVERTERS; i++) {
-                snprintf(mVal, 20, "ctrl/limit/%d", i);
-                subscribe(mVal, QOS_2);
-                snprintf(mVal, 20, "ctrl/restart/%d", i);
-                subscribe(mVal);
-                snprintf(mVal, 20, "ctrl/power/%d", i);
-                subscribe(mVal);
+                snprintf(mVal.data(), mVal.size(), "ctrl/limit/%d", i);
+                subscribe(mVal.data(), QOS_2);
+                snprintf(mVal.data(), mVal.size(), "ctrl/restart/%d", i);
+                subscribe(mVal.data());
+                snprintf(mVal.data(), mVal.size(), "ctrl/power/%d", i);
+                subscribe(mVal.data());
             }
             subscribe(subscr[MQTT_SUBS_SET_TIME]);
         }
@@ -359,11 +362,9 @@ class PubMqtt {
         }
 
         void discoveryConfigLoop(void) {
-            char topic[64], name[32], uniq_id[32], buf[350];
             DynamicJsonDocument doc(256);
 
-            uint8_t fldTotal[4] = {FLD_PAC, FLD_YT, FLD_YD, FLD_PDC};
-            const char* unitTotal[4] = {"W", "kWh", "Wh", "W"};
+            constexpr static uint8_t fldTotal[] = {FLD_PAC, FLD_YT, FLD_YD, FLD_PDC};
 
             String node_id = String(mDevName) + "_TOTAL";
             bool total = (mDiscovery.lastIvId == MAX_NUM_INVERTERS);
@@ -392,32 +393,37 @@ class PubMqtt {
                 doc[F("mf")] = F("Hoymiles");
                 JsonObject deviceObj = doc.as<JsonObject>(); // deviceObj is only pointer!?
 
+                std::array<char, 64> topic;
+                std::array<char, 32> name;
+                std::array<char, 32> uniq_id;
+                std::array<char, 350> buf;
                 const char *devCls, *stateCls;
                 if (!total) {
                     if (rec->assign[mDiscovery.sub].ch == CH0)
-                        snprintf(name, 32, "%s", iv->getFieldName(mDiscovery.sub, rec));
+                        snprintf(name.data(), name.size(), "%s", iv->getFieldName(mDiscovery.sub, rec));
                     else
-                        snprintf(name, 32, "CH%d_%s", rec->assign[mDiscovery.sub].ch, iv->getFieldName(mDiscovery.sub, rec));
-                    snprintf(topic, 64, "/ch%d/%s", rec->assign[mDiscovery.sub].ch, iv->getFieldName(mDiscovery.sub, rec));
-                    snprintf(uniq_id, 32, "ch%d_%s", rec->assign[mDiscovery.sub].ch, iv->getFieldName(mDiscovery.sub, rec));
+                        snprintf(name.data(), name.size(), "CH%d_%s", rec->assign[mDiscovery.sub].ch, iv->getFieldName(mDiscovery.sub, rec));
+                    snprintf(topic.data(), name.size(), "/ch%d/%s", rec->assign[mDiscovery.sub].ch, iv->getFieldName(mDiscovery.sub, rec));
+                    snprintf(uniq_id.data(), uniq_id.size(), "ch%d_%s", rec->assign[mDiscovery.sub].ch, iv->getFieldName(mDiscovery.sub, rec));
 
                     devCls = getFieldDeviceClass(rec->assign[mDiscovery.sub].fieldId);
                     stateCls = getFieldStateClass(rec->assign[mDiscovery.sub].fieldId);
                 }
 
                 else { // total values
-                    snprintf(name, 32, "Total %s", fields[fldTotal[mDiscovery.sub]]);
-                    snprintf(topic, 64, "/%s", fields[fldTotal[mDiscovery.sub]]);
-                    snprintf(uniq_id, 32, "total_%s", fields[fldTotal[mDiscovery.sub]]);
+                    snprintf(name.data(), name.size(), "Total %s", fields[fldTotal[mDiscovery.sub]]);
+                    snprintf(topic.data(), topic.size(), "/%s", fields[fldTotal[mDiscovery.sub]]);
+                    snprintf(uniq_id.data(), uniq_id.size(), "total_%s", fields[fldTotal[mDiscovery.sub]]);
                     devCls = getFieldDeviceClass(fldTotal[mDiscovery.sub]);
                     stateCls = getFieldStateClass(fldTotal[mDiscovery.sub]);
                 }
 
                 DynamicJsonDocument doc2(512);
+                constexpr static char* unitTotal[] = {"W", "kWh", "Wh", "W"};
                 doc2[F("name")] = name;
-                doc2[F("stat_t")] = String(mCfgMqtt->topic) + "/" + ((!total) ? String(iv->config->name) : "total" ) + String(topic);
+                doc2[F("stat_t")] = String(mCfgMqtt->topic) + "/" + ((!total) ? String(iv->config->name) : "total" ) + String(topic.data());
                 doc2[F("unit_of_meas")] = ((!total) ? (iv->getUnit(mDiscovery.sub, rec)) : (unitTotal[mDiscovery.sub]));
-                doc2[F("uniq_id")] = ((!total) ? (String(iv->config->serial.u64, HEX)) : (node_id)) + "_" + uniq_id;
+                doc2[F("uniq_id")] = ((!total) ? (String(iv->config->serial.u64, HEX)) : (node_id)) + "_" + uniq_id.data();
                 doc2[F("dev")] = deviceObj;
                 if (!(String(stateCls) == String("total_increasing")))
                     doc2[F("exp_aft")] = MQTT_INTERVAL + 5;  // add 5 sec if connection is bad or ESP too slow @TODO: stimmt das wirklich als expire!?
@@ -427,13 +433,13 @@ class PubMqtt {
                     doc2[F("stat_cla")] = String(stateCls);
 
                 if (!total)
-                    snprintf(topic, 64, "%s/sensor/%s/ch%d_%s/config", MQTT_DISCOVERY_PREFIX, iv->config->name, rec->assign[mDiscovery.sub].ch, iv->getFieldName(mDiscovery.sub, rec));
+                    snprintf(topic.data(), topic.size(), "%s/sensor/%s/ch%d_%s/config", MQTT_DISCOVERY_PREFIX, iv->config->name, rec->assign[mDiscovery.sub].ch, iv->getFieldName(mDiscovery.sub, rec));
                 else // total values
-                    snprintf(topic, 64, "%s/sensor/%s/total_%s/config", MQTT_DISCOVERY_PREFIX, node_id.c_str(), fields[fldTotal[mDiscovery.sub]]);
+                    snprintf(topic.data(), topic.size(), "%s/sensor/%s/total_%s/config", MQTT_DISCOVERY_PREFIX, node_id.c_str(), fields[fldTotal[mDiscovery.sub]]);
                 size_t size = measureJson(doc2) + 1;
-                memset(buf, 0, size);
-                serializeJson(doc2, buf, size);
-                publish(topic, buf, true, false);
+                buf.fill(0);
+                serializeJson(doc2, buf.data(), size);
+                publish(topic.data(), buf.data(), true, false);
 
                 if(++mDiscovery.sub == ((!total) ? (rec->length) : 4)) {
                     mDiscovery.sub = 0;
@@ -503,15 +509,15 @@ class PubMqtt {
                     mLastIvState[id] = status;
                     changed = true;
 
-                    snprintf(mSubTopic, 32 + MAX_NAME_LENGTH, "%s/available", iv->config->name);
-                    snprintf(mVal, 40, "%d", (uint8_t)status);
-                    publish(mSubTopic, mVal, true);
+                    snprintf(mSubTopic.data(), mSubTopic.size(), "%s/available", iv->config->name);
+                    snprintf(mVal.data(), mVal.size(), "%d", (uint8_t)status);
+                    publish(mSubTopic.data(), mVal.data(), true);
                 }
             }
 
             if(changed) {
-                snprintf(mVal, 32, "%d", ((allAvail) ? MQTT_STATUS_ONLINE : ((anyAvail) ? MQTT_STATUS_PARTIAL : MQTT_STATUS_OFFLINE)));
-                publish("status", mVal, true);
+                snprintf(mVal.data(), mVal.size(), "%d", ((allAvail) ? MQTT_STATUS_ONLINE : ((anyAvail) ? MQTT_STATUS_PARTIAL : MQTT_STATUS_OFFLINE)));
+                publish("status", mVal.data(), true);
             }
 
             return anyAvail;
@@ -533,19 +539,19 @@ class PubMqtt {
 
                 mSendAlarm[i] = false;
 
-                snprintf(mSubTopic, 32 + MAX_NAME_LENGTH, "%s/alarm/cnt", iv->config->name);
-                snprintf(mVal, 40, "%d", iv->alarmCnt);
-                publish(mSubTopic, mVal, false);
+                snprintf(mSubTopic.data(), mSubTopic.size(), "%s/alarm/cnt", iv->config->name);
+                snprintf(mVal.data(), mVal.size(), "%d", iv->alarmCnt);
+                publish(mSubTopic.data(), mVal.data(), false);
 
                 for(uint8_t j = 0; j < 10; j++) {
                     if(0 != iv->lastAlarm[j].code) {
-                        snprintf(mSubTopic, 32 + MAX_NAME_LENGTH, "%s/alarm/%d", iv->config->name, j);
-                        snprintf(mVal, 100, "{\"code\":%d,\"str\":\"%s\",\"start\":%d,\"end\":%d}",
+                        snprintf(mSubTopic.data(), mSubTopic.size(), "%s/alarm/%d", iv->config->name, j);
+                        snprintf(mVal.data(), mVal.size(), "{\"code\":%d,\"str\":\"%s\",\"start\":%d,\"end\":%d}",
                             iv->lastAlarm[j].code,
                             iv->getAlarmStr(iv->lastAlarm[j].code).c_str(),
                             iv->lastAlarm[j].start + lastMidnight,
                             iv->lastAlarm[j].end + lastMidnight);
-                        publish(mSubTopic, mVal, false);
+                        publish(mSubTopic.data(), mVal.data(), false);
                         yield();
                     }
                 }
@@ -575,9 +581,9 @@ class PubMqtt {
                         }
                     }
 
-                    snprintf(mSubTopic, 32 + MAX_NAME_LENGTH, "%s/ch%d/%s", iv->config->name, rec->assign[i].ch, fields[rec->assign[i].fieldId]);
-                    snprintf(mVal, 40, "%g", ah::round3(iv->getValue(i, rec)));
-                    publish(mSubTopic, mVal, retained);
+                    snprintf(mSubTopic.data(), mSubTopic.size(), "%s/ch%d/%s", iv->config->name, rec->assign[i].ch, fields[rec->assign[i].fieldId]);
+                    snprintf(mVal.data(), mVal.size(), "%g", ah::round3(iv->getValue(i, rec)));
+                    publish(mSubTopic.data(), mVal.data(), retained);
 
                     yield();
                 }
@@ -597,33 +603,33 @@ class PubMqtt {
         }
 
         espMqttClient mClient;
-        cfgMqtt_t *mCfgMqtt;
+        cfgMqtt_t *mCfgMqtt = nullptr;
         #if defined(ESP8266)
         WiFiEventHandler mHWifiCon, mHWifiDiscon;
         #endif
 
-        HMSYSTEM *mSys;
+        HMSYSTEM *mSys = nullptr;
         PubMqttIvData<HMSYSTEM> mSendIvData;
 
-        uint32_t *mUtcTimestamp, *mUptime;
-        uint32_t mRxCnt, mTxCnt;
+        uint32_t *mUtcTimestamp = nullptr, *mUptime = nullptr;
+        uint32_t mRxCnt = 0, mTxCnt = 0;
         std::queue<sendListCmdIv> mSendList;
-        std::array<bool, MAX_NUM_INVERTERS> mSendAlarm{};
-        subscriptionCb mSubscriptionCb;
-        bool mLastAnyAvail;
-        InverterStatus mLastIvState[MAX_NUM_INVERTERS];
-        uint32_t mIvLastRTRpub[MAX_NUM_INVERTERS];
-        uint16_t mIntervalTimeout;
+        std::array<bool, MAX_NUM_INVERTERS> mSendAlarm;
+        subscriptionCb mSubscriptionCb = nullptr;
+        bool mLastAnyAvail = false;
+        std::array<InverterStatus, MAX_NUM_INVERTERS> mLastIvState;
+        std::array<uint32_t, MAX_NUM_INVERTERS> mIvLastRTRpub;
+        uint16_t mIntervalTimeout = 0;
 
         // last will topic and payload must be available through lifetime of 'espMqttClient'
-        char mLwtTopic[MQTT_TOPIC_LEN+5];
-        const char *mDevName, *mVersion;
-        char mClientId[24]; // number of chars is limited to 23 up to v3.1 of MQTT
+        std::array<char, (MQTT_TOPIC_LEN + 5)> mLwtTopic;
+        const char *mDevName = nullptr, *mVersion = nullptr;
+        std::array<char, 24> mClientId; // number of chars is limited to 23 up to v3.1 of MQTT
         // global buffer for mqtt topic. Used when publishing mqtt messages.
-        char mTopic[MQTT_TOPIC_LEN + 32 + MAX_NAME_LENGTH + 1];
-        char mSubTopic[32 + MAX_NAME_LENGTH + 1];
-        char mVal[100];
-        discovery_t mDiscovery;
+        std::array<char, (MQTT_TOPIC_LEN + 32 + MAX_NAME_LENGTH + 1)> mTopic;
+        std::array<char, (32 + MAX_NAME_LENGTH + 1)> mSubTopic;
+        std::array<char, 100> mVal;
+        discovery_t mDiscovery = {true, 0, 0, 0};
 };
 
 #endif /*ENABLE_MQTT*/
diff --git a/src/publisher/pubMqttIvData.h b/src/publisher/pubMqttIvData.h
index cfed38b92..4405d037c 100644
--- a/src/publisher/pubMqttIvData.h
+++ b/src/publisher/pubMqttIvData.h
@@ -205,9 +205,9 @@ class PubMqttIvData {
         }
 
         void stateSendTotals() {
-            uint8_t fieldId;
             mRTRDataHasBeenSent = true;
             if(mPos < 5) {
+                uint8_t fieldId;
                 bool retained = true;
                 switch (mPos) {
                     default:
diff --git a/src/publisher/pubSerial.h b/src/publisher/pubSerial.h
index 34dc64f26..9ac245931 100644
--- a/src/publisher/pubSerial.h
+++ b/src/publisher/pubSerial.h
@@ -1,6 +1,6 @@
 //-----------------------------------------------------------------------------
-// 2022 Ahoy, https://ahoydtu.de
-// Creative Commons - http://creativecommons.org/licenses/by-nc-sa/3.0/de/
+// 2024 Ahoy, https://github.com/lumpapu/ahoy
+// Creative Commons - http://creativecommons.org/licenses/by-nc-sa/4.0/deed
 //-----------------------------------------------------------------------------
 
 #ifndef __PUB_SERIAL_H__
@@ -13,8 +13,6 @@
 template<class HMSYSTEM>
 class PubSerial {
     public:
-        PubSerial() {}
-
         void setup(settings_t *cfg, HMSYSTEM *sys, uint32_t *utcTs) {
             mCfg = cfg;
             mSys = sys;
@@ -46,9 +44,9 @@ class PubSerial {
         }
 
     private:
-        settings_t *mCfg;
-        HMSYSTEM *mSys;
-        uint32_t *mUtcTimestamp;
+        settings_t *mCfg = nullptr;
+        HMSYSTEM *mSys = nullptr;
+        uint32_t *mUtcTimestamp = nullptr;
 };
 
 
diff --git a/src/utils/improv.h b/src/utils/improv.h
index d5a9ae743..32bc403c1 100644
--- a/src/utils/improv.h
+++ b/src/utils/improv.h
@@ -10,6 +10,7 @@
 #include <functional>
 #include "dbg.h"
 #include "AsyncJson.h"
+#include "../appInterface.h"
 
 // https://www.improv-wifi.com/serial/
 // https://github.com/jnthas/improv-wifi-demo/blob/main/src/esp32-wifiimprov/esp32-wifiimprov.ino
@@ -78,7 +79,7 @@ class Improv {
             DBGPRINTLN("");
         }
 
-        inline uint8_t buildChecksum(uint8_t buf[], uint8_t len) {
+        inline uint8_t buildChecksum(const uint8_t buf[], uint8_t len) {
             uint8_t calc = 0;
             for(uint8_t i = 0; i < len; i++) {
                 calc += buf[i];
@@ -86,7 +87,7 @@ class Improv {
             return calc;
         }
 
-        inline bool checkChecksum(uint8_t buf[], uint8_t len) {
+        inline bool checkChecksum(const uint8_t buf[], uint8_t len) {
             /*DHEX(buf[len], false);
             DBGPRINT(F(" == "), false);
             DBGHEXLN(buildChecksum(buf, len), false);*/
@@ -97,7 +98,7 @@ class Improv {
             if(len < 11)
                 return false;
 
-            if(0 != strncmp((char*)buf, "IMPROV", 6))
+            if(0 != strncmp(reinterpret_cast<char*>(buf), "IMPROV", 6))
                 return false;
 
             // version check (only version 1 is supported!)
@@ -199,7 +200,7 @@ class Improv {
             dumpBuf(buf, len);
         }
 
-        void parsePayload(uint8_t type, uint8_t buf[], uint8_t len) {
+        void parsePayload(uint8_t type, const uint8_t buf[], uint8_t len) {
             if(TYPE_RPC == type) {
                 if(GET_CURRENT_STATE == buf[0]) {
                     setDebugEn(false);
@@ -212,9 +213,10 @@ class Improv {
             }
         }
 
-        IApp *mApp;
-        const char *mDevName, *mVersion;
-        bool mScanRunning;
+        IApp *mApp = nullptr;
+        const char *mDevName = nullptr;
+        const char *mVersion = nullptr;
+        bool mScanRunning = false;
 };
 #endif
 
diff --git a/src/utils/scheduler.h b/src/utils/scheduler.h
index 751550df8..160097787 100644
--- a/src/utils/scheduler.h
+++ b/src/utils/scheduler.h
@@ -7,6 +7,7 @@
 #define __SCHEDULER_H__
 
 #include <functional>
+#include <array>
 #include "dbg.h"
 
 namespace ah {
@@ -28,8 +29,6 @@ namespace ah {
 
     class Scheduler {
         public:
-            Scheduler() {}
-
             void setup(bool directStart) {
                 mUptime     = 0;
                 mTimestamp  = (directStart) ? 1 : 0;
@@ -93,8 +92,7 @@ namespace ah {
             }
 
             inline void resetTicker(void) {
-                for (uint8_t i = 0; i < MAX_NUM_TICKER; i++)
-                    mTickerInUse[i] = false;
+                mTickerInUse.fill(false);
             }
 
             void getStat(uint8_t *max) {
@@ -159,11 +157,11 @@ namespace ah {
                 }
             }
 
-            sP mTicker[MAX_NUM_TICKER];
-            bool mTickerInUse[MAX_NUM_TICKER];
-            uint32_t mMillis, mPrevMillis, mDiff;
-            uint8_t mDiffSeconds;
-            uint8_t mMax;
+            std::array<sP, MAX_NUM_TICKER> mTicker;
+            std::array<bool, MAX_NUM_TICKER> mTickerInUse;
+            uint32_t mMillis = 0, mPrevMillis = 0, mDiff = 0;
+            uint8_t mDiffSeconds = 0;
+            uint8_t mMax = 0;
     };
 }
 
diff --git a/src/utils/spiPatcher.h b/src/utils/spiPatcher.h
index 2f8ce616f..210b2a094 100644
--- a/src/utils/spiPatcher.h
+++ b/src/utils/spiPatcher.h
@@ -16,7 +16,7 @@
 
 class SpiPatcher {
     protected:
-        SpiPatcher(spi_host_device_t dev) :
+        explicit SpiPatcher(spi_host_device_t dev) :
             mHostDevice(dev), mCurHandle(nullptr) {
             // Use binary semaphore instead of mutex for performance reasons
             mutex = xSemaphoreCreateBinaryStatic(&mutex_buffer);
diff --git a/src/utils/timemonitor.h b/src/utils/timemonitor.h
index 9f99cc92f..18ab51d96 100644
--- a/src/utils/timemonitor.h
+++ b/src/utils/timemonitor.h
@@ -22,14 +22,14 @@ class TimeMonitor {
         /**
          * A constructor for creating a TimeMonitor object
          */
-        TimeMonitor(void) {}
+        TimeMonitor() {}
 
         /**
          * A constructor for initializing a TimeMonitor object
          * @param timeout timeout in ms
          * @param start   (optional) if true, start TimeMonitor immediately
          */
-        TimeMonitor(uint32_t timeout, bool start = false) {
+        explicit TimeMonitor(uint32_t timeout, bool start = false) {
             if (start)
                 startTimeMonitor(timeout);
             else
@@ -80,7 +80,7 @@ class TimeMonitor {
          *         true:  TimeMonitor already timed out
          *         false: TimeMonitor still in time or TimeMonitor was stopped
          */
-        bool isTimeout(void) {
+        bool isTimeout(void) const {
             if ((mStarted) && ((millis() - mStartTime) >= mTimeout))
                 return true;
             else
diff --git a/src/web/RestApi.h b/src/web/RestApi.h
index 564d6c622..acd085f3c 100644
--- a/src/web/RestApi.h
+++ b/src/web/RestApi.h
@@ -141,7 +141,7 @@ class RestApi {
             #endif
         }
 
-        void onApiPostBody(AsyncWebServerRequest *request, uint8_t *data, size_t len, size_t index, size_t total) {
+        void onApiPostBody(AsyncWebServerRequest *request, const uint8_t *data, size_t len, size_t index, size_t total) {
             DPRINTLN(DBG_VERBOSE, "onApiPostBody");
 
             if(0 == index) {
@@ -158,7 +158,7 @@ class RestApi {
 
             DynamicJsonDocument json(1000);
 
-            DeserializationError err = deserializeJson(json, (const char *)mTmpBuf, mTmpSize);
+            DeserializationError err = deserializeJson(json, reinterpret_cast<const char*>(mTmpBuf), mTmpSize);
             JsonObject obj = json.as<JsonObject>();
 
             AsyncJsonResponse* response = new AsyncJsonResponse(false, 200);
@@ -930,20 +930,20 @@ class RestApi {
             return true;
         }
 
-        IApp *mApp;
-        HMSYSTEM *mSys;
-        HmRadio<> *mRadioNrf;
+        IApp *mApp = nullptr;
+        HMSYSTEM *mSys = nullptr;
+        HmRadio<> *mRadioNrf = nullptr;
         #if defined(ESP32)
-        CmtRadio<> *mRadioCmt;
+        CmtRadio<> *mRadioCmt = nullptr;
         #endif
-        AsyncWebServer *mSrv;
-        settings_t *mConfig;
+        AsyncWebServer *mSrv = nullptr;
+        settings_t *mConfig = nullptr;
 
-        uint32_t mTimezoneOffset;
-        uint32_t mHeapFree, mHeapFreeBlk;
-        uint8_t mHeapFrag;
+        uint32_t mTimezoneOffset = 0;
+        uint32_t mHeapFree = 0, mHeapFreeBlk = 0;
+        uint8_t mHeapFrag = 0;
         uint8_t *mTmpBuf = NULL;
-        uint32_t mTmpSize;
+        uint32_t mTmpSize = 0;
 };
 
 #endif /*__WEB_API_H__*/
diff --git a/src/web/web.h b/src/web/web.h
index 0ffd0594e..a166377f6 100644
--- a/src/web/web.h
+++ b/src/web/web.h
@@ -48,9 +48,6 @@ class Web {
    public:
         Web(void) : mWeb(80), mEvts("/events") {
             memset(mSerialBuf, 0, WEB_SERIAL_BUF_SIZE);
-            mSerialBufFill     = 0;
-            mSerialAddTime     = true;
-            mSerialClientConnnected = false;
         }
 
         void setup(IApp *app, HMSYSTEM *sys, settings_t *config) {
@@ -490,9 +487,8 @@ class Web {
 
 
             // pinout
-            uint8_t pin;
             for (uint8_t i = 0; i < 16; i++) {
-                pin = request->arg(String(pinArgNames[i])).toInt();
+                uint8_t pin = request->arg(String(pinArgNames[i])).toInt();
                 switch(i) {
                     case 0:  mConfig->nrf.pinCs    = ((pin != 0xff) ? pin : DEF_NRF_CS_PIN);  break;
                     case 1:  mConfig->nrf.pinCe    = ((pin != 0xff) ? pin : DEF_NRF_CE_PIN);  break;
@@ -633,8 +629,8 @@ class Web {
         // NOTE: Grouping for fields with channels and totals is currently not working
         // TODO: Handle grouping and sorting for independant from channel number
         // NOTE: Check packetsize for MAX_NUM_INVERTERS. Successfully Tested with 4 Inverters (each with 4 channels)
-        const char * metricConstPrefix = "ahoy_solar_";
-        const char * metricConstInverterFormat = " {inverter=\"%s\"} %d\n";
+        const char* metricConstPrefix = "ahoy_solar_";
+        const char* metricConstInverterFormat = " {inverter=\"%s\"} %d\n";
         typedef enum {
             metricsStateInverterInfo=0,           metricsStateInverterEnabled=1,        metricsStateInverterAvailable=2,
             metricsStateInverterProducing=3,      metricsStateInverterPowerLimitRead=4, metricsStateInverterPowerLimitAck=5,
@@ -648,7 +644,7 @@ class Web {
             metricsStateStart,
             metricsStateEnd
         } MetricStep_t;
-        MetricStep_t metricsStep;
+        MetricStep_t metricsStep = metricsStateInverterInfo;
         typedef struct {
             const char *topic;
             const char *type;
@@ -674,9 +670,6 @@ class Web {
             { "radio_dtu_loss_cnt",   "counter" ,metricConstInverterFormat, [](Inverter<> *iv)-> uint64_t {return iv->radioStatistics.dtuLoss;} },
             { "radio_dtu_sent_cnt",   "counter" ,metricConstInverterFormat, [](Inverter<> *iv)-> uint64_t {return iv->radioStatistics.dtuSent;} }
         };
-        int metricsInverterId;
-        uint8_t metricsFieldId;
-        bool metricDeclared, metricTotalDeclard;
 
         void showMetrics(AsyncWebServerRequest *request) {
             DPRINTLN(DBG_VERBOSE, F("web::showMetrics"));
@@ -715,7 +708,7 @@ class Web {
                         snprintf(topic,sizeof(topic),"%swifi_rssi_db{devicename=\"%s\"} %d\n",metricConstPrefix, mConfig->sys.deviceName, WiFi.RSSI());
                         metrics += String(type) + String(topic);
 
-                        len = snprintf((char *)buffer,maxLen,"%s",metrics.c_str());
+                        len = snprintf(reinterpret_cast<char*>(buffer), maxLen,"%s",metrics.c_str());
                         // Next is Inverter information
                         metricsStep = metricsStateInverterInfo;
                         break;
@@ -743,7 +736,7 @@ class Web {
                                         (String("ahoy_solar_inverter_") + inverterMetrics[metricsStep].topic +
                                             inverterMetrics[metricsStep].format).c_str(),
                                             inverterMetrics[metricsStep].valueFunc);
-                        len = snprintf((char *)buffer,maxLen,"%s",metrics.c_str());
+                        len = snprintf(reinterpret_cast<char*>(buffer), maxLen, "%s", metrics.c_str());
                         // ugly hack to increment the enum
                         metricsStep = static_cast<MetricStep_t>( static_cast<int>(metricsStep) + 1);
                         // Prepare  Realtime Field loop, which may be startet next
@@ -763,7 +756,7 @@ class Web {
                             metrics = "# Info: all realtime fields processed\n";
                             metricsStep = metricsStateAlarmData;
                         }
-                        len = snprintf((char *)buffer,maxLen,"%s",metrics.c_str());
+                        len = snprintf(reinterpret_cast<char *>(buffer), maxLen, "%s", metrics.c_str());
                         break;
 
                   case metricStateRealtimeInverterId: // Iterate over all inverters for this field
@@ -837,7 +830,7 @@ class Web {
                             metricsFieldId++; // Process next field Id
                             metricsStep = metricStateRealtimeFieldId;
                         }
-                        len = snprintf((char *)buffer,maxLen,"%s",metrics.c_str());
+                        len = snprintf(reinterpret_cast<char *>(buffer), maxLen, "%s", metrics.c_str());
                         break;
 
                     case metricsStateAlarmData: // Alarm Info loop : fit to one packet
@@ -861,7 +854,7 @@ class Web {
                                 }
                             }
                         }
-                        len = snprintf((char*)buffer,maxLen,"%s",metrics.c_str());
+                        len = snprintf(reinterpret_cast<char*>(buffer), maxLen, "%s", metrics.c_str());
                         metricsStep = metricsStateEnd;
                         break;
 
@@ -880,10 +873,9 @@ class Web {
 
         // Traverse all inverters and collect the metric via valueFunc
         String inverterMetric(char *buffer, size_t len, const char *format, std::function<uint64_t(Inverter<> *iv)> valueFunc) {
-            Inverter<> *iv;
             String metric = "";
             for (int metricsInverterId = 0; metricsInverterId < mSys->getNumInverters();metricsInverterId++) {
-                iv = mSys->getInverterByPos(metricsInverterId);
+                Inverter<> *iv = mSys->getInverterByPos(metricsInverterId);
                 if (NULL != iv) {
                     snprintf(buffer,len,format,iv->config->name, valueFunc(iv));
                     metric += String(buffer);
@@ -904,21 +896,27 @@ class Web {
             if(shortUnit == "Hz")   return {"_hertz", "gauge"};
             return {"", "gauge"};
         }
+
+    private:
+        int metricsInverterId = 0;
+        uint8_t metricsFieldId = 0;
+        bool metricDeclared = false, metricTotalDeclard = false;
 #endif
+    private:
         AsyncWebServer mWeb;
         AsyncEventSource mEvts;
-        IApp *mApp;
-        HMSYSTEM *mSys;
+        IApp *mApp = nullptr;
+        HMSYSTEM *mSys = nullptr;
 
-        settings_t *mConfig;
+        settings_t *mConfig = nullptr;
 
-        bool mSerialAddTime;
+        bool mSerialAddTime = true;
         char mSerialBuf[WEB_SERIAL_BUF_SIZE];
-        uint16_t mSerialBufFill;
-        bool mSerialClientConnnected;
+        uint16_t mSerialBufFill = 0;
+        bool mSerialClientConnnected = false;
 
         File mUploadFp;
-        bool mUploadFail;
+        bool mUploadFail = false;
 };
 
 #endif /*__WEB_H__*/
diff --git a/src/wifi/ahoywifi.h b/src/wifi/ahoywifi.h
index 709c08c43..d38701aa6 100644
--- a/src/wifi/ahoywifi.h
+++ b/src/wifi/ahoywifi.h
@@ -71,7 +71,7 @@ class ahoywifi {
         void welcome(String ip, String mode);
 
 
-        settings_t *mConfig = NULL;
+        settings_t *mConfig = nullptr;
         appWifiCb mAppWifiCb;
 
         DNSServer mDns;
@@ -81,15 +81,15 @@ class ahoywifi {
         WiFiEventHandler wifiConnectHandler, wifiDisconnectHandler, wifiGotIPHandler;
         #endif
 
-        WiFiStatus_t mStaConn;
-        uint8_t mCnt;
-        uint32_t *mUtcTimestamp;
+        WiFiStatus_t mStaConn = DISCONNECTED;
+        uint8_t mCnt = 0;
+        uint32_t *mUtcTimestamp = nullptr;
 
-        uint8_t mScanCnt;
-        bool mScanActive;
-        bool mGotDisconnect;
+        uint8_t mScanCnt = 0;
+        bool mScanActive = false;
+        bool mGotDisconnect = false;
         std::list<uint8_t> mBSSIDList;
-        bool mStopApAllowed;
+        bool mStopApAllowed = false;
         bool mWasInCh12to14 = false;
 };