diff --git a/ismas/ismas_client.cpp b/ismas/ismas_client.cpp
index 7c57811..a842180 100644
--- a/ismas/ismas_client.cpp
+++ b/ismas/ismas_client.cpp
@@ -3,6 +3,24 @@
 #include <cstring>
 #include <cstdio>
 
+#include <errno.h>
+#include <arpa/inet.h> // inet_addr()
+#include <netdb.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <netinet/in.h>
+#include <netinet/tcp.h>
+#include <string.h>
+#include <strings.h> // bzero()
+#include <sys/socket.h>
+#include <unistd.h> // read(), write(), close()
+#include <fcntl.h>
+
+
+#include <QThread>
+#include <QJsonDocument>
+#include <QJsonObject>
+
 #if 0
 # $1: EVENT: U0001 update finished: 100%
 #            U0002 reset TRG
@@ -24,6 +42,208 @@
 #include <QDateTime>
 #include <QDebug>
 
+void IsmasClient::printDebugMessage(int port,
+                                    QString const &clientIP,
+                                    int clientPort,
+                                    QString const &message) {
+    qDebug().noquote()
+        << "\n"
+        << "SEND-REQUEST-RECEIVE-RESPONSE ..." << "\n"
+        << "hostname ........" << "127.0.0.1"  << "\n"
+        << "port ............" << port << "\n"
+        << "local address ..." << clientIP << "\n"
+        << "local port ......" << clientPort << "\n"
+        << message;
+}
+
+void IsmasClient::printInfoMessage(int port,
+                                   QString const &clientIP,
+                                   int clientPort,
+                                   QString const &message) {
+    qInfo().noquote()
+        << "\n"
+        << "SEND-REQUEST-RECEIVE-RESPONSE ..." << "\n"
+        << "hostname ........" << "127.0.0.1"  << "\n"
+        << "port ............" << port << "\n"
+        << "local address ..." << clientIP << "\n"
+        << "local port ......" << clientPort << "\n"
+        << message;
+}
+
+void IsmasClient::printErrorMessage(int port,
+                                    QString const &clientIP,
+                                    int clientPort,
+                                    QString const &message) {
+    qCritical().noquote()
+        << "\n"
+        << "SEND-REQUEST-RECEIVE-RESPONSE ..." << "\n"
+        << "hostname ........" << "127.0.0.1"  << "\n"
+        << "port ............" << port << "\n"
+        << "local address ..." << clientIP << "\n"
+        << "local port ......" << clientPort << "\n"
+        << message;
+}
+
+std::optional<QString>
+IsmasClient::sendRequestReceiveResponse(int port, QString const &request) {
+
+    qInfo() << "REQUEST" << request;
+
+    int sockfd;
+    int r;
+    errno = 0;
+    // socket create and verification
+    if ((sockfd = ::socket(AF_INET, SOCK_STREAM, 0)) == -1) {
+        qCritical().noquote()
+            << "\n"
+            << "SEND-REQUEST-RECEIVE-RESPONSE ..." << "\n"
+            << "SOCKET CREATION FAILED (" << strerror(errno) << ")";
+        return std::nullopt;
+    }
+
+    struct sockaddr_in servAddr;
+    bzero(&servAddr, sizeof(servAddr));
+    // assign IP, PORT
+    servAddr.sin_family = AF_INET;
+    servAddr.sin_addr.s_addr = inet_addr("127.0.0.1");
+
+    servAddr.sin_port = htons(port);
+    // connect the client socket to server socket
+    if ((r = ::connect(sockfd, (struct sockaddr *)(&servAddr), sizeof(servAddr))) != 0) {
+        qCritical().noquote()
+            << "\n"
+            << "SEND-REQUEST-RECEIVE-RESPONSE ..." << "\n"
+            << "CONNECTION WITH SERVER FAILED (" << strerror(r) << ")";
+        ::close(sockfd);
+        return std::nullopt;
+    }
+
+    struct sockaddr_in clientAddr;
+    bzero(&clientAddr, sizeof(clientAddr));
+    socklen_t sockLen = sizeof(clientAddr);
+
+    char clientIP[16];
+    bzero(&clientIP, sizeof(clientIP));
+    getsockname(sockfd, (struct sockaddr *)(&clientAddr), &sockLen);
+    inet_ntop(AF_INET, &clientAddr.sin_addr, clientIP, sizeof(clientIP));
+    unsigned int clientPort = ntohs(clientAddr.sin_port);
+
+    printDebugMessage(port, clientIP, clientPort, QString("CONNECTED TO SERVER"));
+
+    struct timeval tv;
+    tv.tv_sec = 10;  /* 10 secs timeout for read and write */
+
+    struct linger so_linger;
+    so_linger.l_onoff = 1;
+    so_linger.l_linger = 0;
+
+    setsockopt(sockfd, SOL_SOCKET, SO_LINGER, &so_linger, sizeof(so_linger));
+    setsockopt(sockfd, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv));
+    setsockopt(sockfd, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
+    int flag = 1;
+    setsockopt(sockfd, IPPROTO_TCP, TCP_NODELAY, (char *) &flag, sizeof(int));
+
+    static char buf[1024*8];
+    bzero(buf, sizeof(buf));
+    int const bytesToWrite = strlen(request.toStdString().c_str());
+    strncpy(buf, request.toStdString().c_str(), sizeof(buf)-1);
+
+    int bytesWritten = 0;
+    while (bytesWritten < bytesToWrite) {
+        int n = ::sendto(sockfd, buf+bytesWritten, bytesToWrite-bytesWritten, 0, NULL, 0);
+        if (n >= 0) {
+            bytesWritten += n;
+        } else {
+            if (errno == EWOULDBLOCK) {
+                printErrorMessage(port, clientIP, clientPort,
+                    QString("TIMEOUT  (") + strerror(errno) + ")");
+                ::close(sockfd);
+                return std::nullopt;
+            } else
+            if (errno == EINTR) {
+                printErrorMessage(port, clientIP, clientPort,
+                    QString("INTERRUPTED BY SIGNAL (1) (") + strerror(errno) + ")");
+                continue;
+            }
+        }
+    }
+
+    // DO NOT USE SHUTDOWN! APISM CAN NOT COPE WITH IT
+    // errno = 0;
+    // if (shutdown(sockfd, SHUT_WR) < 0) {
+    //     printErrorMessage(port, clientIP, clientPort,
+    //        QString("CANNOT CLOSE WRITING END (") + strerror(errno) + ")");
+    // }
+
+    printInfoMessage(port, clientIP, clientPort, QString("MESSAGE SENT ") + buf);
+
+    bzero(buf, sizeof(buf));
+    int bytesToRead = sizeof(buf)-1;
+    int bytesRead = 0;
+    while (bytesRead < bytesToRead) {
+        errno = 0;
+        int n = ::recvfrom(sockfd, buf+bytesRead, bytesToRead-bytesRead,
+                           0, NULL, NULL);
+        if (n > 0) { //
+            bytesRead += n;
+        } else
+        if (n == 0) {
+            // The return value will be 0 when the peer has performed an orderly shutdown.
+            printErrorMessage(port, clientIP, clientPort,
+                QString("PEER CLOSED CONNECTION (") + strerror(errno) + ")");
+            ::close(sockfd);
+            return std::nullopt;
+        } else
+        if (n < 0) {
+            if (errno == EWOULDBLOCK) {
+                printErrorMessage(port, clientIP, clientPort,
+                        QString("TIMEOUT  (") + strerror(errno) + ")");
+                ::close(sockfd);
+                return std::nullopt;
+            }
+            if (errno == EINTR) {
+                printErrorMessage(port, clientIP, clientPort,
+                    QString("INTERRUPTED BY SIGNAL (2) (") + strerror(errno) + ")");
+                continue;
+            }
+        }
+
+        printInfoMessage(port, clientIP, clientPort, QString("MESSAGE RECEIVED ") + buf);
+        QString response(buf);
+
+        if (int idx = response.indexOf("{\"error\":\"ISMAS is offline\"}")) {
+            response = response.mid(0, idx);
+        } else
+        if (response == "RECORD SAVED") {
+            printInfoMessage(port, clientIP, clientPort, "IGNORED 'RECORD SAVED' RESPONSE");
+            ::close(sockfd);
+            return std::nullopt;
+        }
+
+        QJsonParseError parseError;
+        QJsonDocument document(QJsonDocument::fromJson(response.toUtf8(), &parseError));
+        if (parseError.error == QJsonParseError::NoError) {
+            if (document.isObject()) { // done: received valid APISM response
+                printInfoMessage(port, clientIP, clientPort,
+                   QString("VALID APISM RESPONSE .. \n") + response);
+                ::close(sockfd);
+                return response;
+            } else {
+                printInfoMessage(port, clientIP, clientPort,
+                   QString("CORRUPTED RESPONSE ") + response);
+                ::close(sockfd);
+                return std::nullopt;
+            }
+        } else {
+            printDebugMessage(port, clientIP, clientPort,
+                QString("PARSE ERROR ") + response + " " + parseError.errorString());
+            ::close(sockfd);
+            return std::nullopt;
+        }
+    }
+    return std::nullopt;
+}
+
 QString IsmasClient::updateNewsToIsmas(char const *event,
                                        int percent,
                                        int resultCode,
@@ -53,6 +273,54 @@ QString IsmasClient::updateNewsToIsmas(char const *event,
     return buf;
 }
 
+QString IsmasClient::errorBackendNotConnected(QString const &info,
+                                              QString const &version) {
+    return updateNewsToIsmas("U0003",
+                             m_progressInPercent,
+                             RESULT_CODE::INSTALL_ERROR,
+                             "CHECK BACKEND CONNECTIVITY",
+                             info.toStdString().c_str(),
+                             version.toStdString().c_str());
+}
+
+QString IsmasClient::backendConnected(QString const &info, QString const &version) {
+    return updateNewsToIsmas("U0010",
+                             m_progressInPercent,
+                             RESULT_CODE::SUCCESS,
+                             "CHECK BACKEND CONNECTIVITY",
+                             info.toStdString().c_str(),
+                             version.toStdString().c_str());
+}
+
+QString IsmasClient::execOpkgCommand(QString const &info, QString const &version) {
+    return updateNewsToIsmas("U0010",
+                             m_progressInPercent,
+                             RESULT_CODE::SUCCESS,
+                             "EXECUTE OPKG COMMAND",
+                             info.toStdString().c_str(),
+                             version.toStdString().c_str());
+}
+
+QString IsmasClient::updateTriggerSet(QString const &info, QString const &version) {
+    return updateNewsToIsmas("U0010",
+                             m_progressInPercent,
+                             RESULT_CODE::SUCCESS,
+                             "CHECK UPDATE TRIGGER",
+                             info.toStdString().c_str(),
+                             version.toStdString().c_str());
+
+}
+
+QString IsmasClient::errorUpdateTrigger(QString const &info, QString const &version) {
+    return updateNewsToIsmas("U0003",
+                             m_progressInPercent,
+                             RESULT_CODE::INSTALL_ERROR,
+                             "CHECK UPDATE TRIGGER",
+                             info.toStdString().c_str(),
+                             version.toStdString().c_str());
+
+}
+
 QString IsmasClient::updateOfPSASendVersion(PSAInstalled const &psa) {
     //static int const constexpr SIZE = 4096*8;
     static char buf[4096*2];
@@ -376,39 +644,101 @@ QString IsmasClient::updateOfPSASendVersion(PSAInstalled const &psa) {
         psa.pluginVersion.prmCalculatePriceConfigUi.toStdString().c_str(),
         psa.pluginVersion.tcpZVT.toStdString().c_str());
 
-    printf("buf=%s\n", buf);
+    qInfo() << buf;
 
     return buf;
 }
 
-
-QString IsmasClient::updateOfPSAActivated() {
+QString IsmasClient::updateOfPSAContinues(QString currentStage,
+                                          QString currentStageInfo,
+                                          QString const &version) {
     return updateNewsToIsmas("U0010",
-                             1,
-                             0,
-                             "activated",
-                             "detected WAIT state",
-                             "1.0.0");
+                             m_progressInPercent,
+                             RESULT_CODE::SUCCESS,
+                             currentStage.toStdString().c_str(),
+                             currentStageInfo.toStdString().c_str(),
+                             version.toStdString().c_str());
 }
 
-QString IsmasClient::updateOfPSASucceeded() {
+QString IsmasClient::updateOfPSAStarted(QString const &version) {
+    return updateNewsToIsmas("U0010",
+                             m_progressInPercent,
+                             RESULT_CODE::SUCCESS,
+                             "START",
+                             "detected WAIT state: start update process",
+                             version.toStdString().c_str());
+}
+
+QString IsmasClient::checkoutBranch(QString const &info, QString const &version) {
+    return updateNewsToIsmas("U0010",
+                             m_progressInPercent,
+                             RESULT_CODE::SUCCESS,
+                             "BRANCH-CHECKOUT",
+                             info.toStdString().c_str(),
+                             version.toStdString().c_str());
+}
+
+QString IsmasClient::cloneAndCheckoutCustomerRepository(QString const &info, QString const &version) { // clone and checkout customer repository
+    return updateNewsToIsmas("U0010",
+                             m_progressInPercent,
+                             RESULT_CODE::SUCCESS,
+                             "CLONE-CHECKOUT",
+                             info.toStdString().c_str(),
+                             version.toStdString().c_str());
+}
+
+QString IsmasClient::gitFetch(QString const &info, QString const &version) {
+    return updateNewsToIsmas("U0010",
+                             m_progressInPercent,
+                             RESULT_CODE::SUCCESS,
+                             "GIT-FETCH",
+                             info.toStdString().c_str(),
+                             version.toStdString().c_str());
+}
+
+QString IsmasClient::errorGitFetch(int resultCode, QString const &info, QString const &version) {
+    return updateNewsToIsmas("U0003",
+                             m_progressInPercent,
+                             resultCode,
+                             "GIT-FETCH-FAILED",
+                             info.toStdString().c_str(),
+                             version.toStdString().c_str());
+}
+
+QString IsmasClient::updateOfPSAActivated(QString const &version) {   // sent even after success
+    m_progressInPercent = 0;
+    return updateNewsToIsmas("U0002",
+                             m_progressInPercent,
+                             RESULT_CODE::SUCCESS,
+                             "UPDATE ACTIVATED",
+                             "reset WAIT state",
+                             version.toStdString().c_str());
+}
+
+QString IsmasClient::updateOfPSASucceeded(QString const &version) {
+    m_progressInPercent = 0;
     return updateNewsToIsmas("U0001",
-                             100,
-                             0,
-                             "update_succeeded",
-                             "",
-                             "1.0.0");
+                             m_progressInPercent,
+                             RESULT_CODE::SUCCESS,
+                             "UPDATE SUCCESS",
+                             "update process succeeded",
+                             version.toStdString().c_str());
 }
 
-QString IsmasClient::setUpdatesAvailable() {
-    return updateNewsToIsmas("U0099",
-                             10,
-                             0,
-                             "set_updates_available",
-                             "",
-                             "");
+QString IsmasClient::sanityCheckFailed(int resultCode, QString reason, QString const &version) {
+    return updateNewsToIsmas("U0003",
+                             m_progressInPercent,
+                             resultCode,
+                             "SANITY-CHECK-FAILED",
+                             reason.toStdString().c_str(),
+                             version.toStdString().c_str());
 }
 
-
-
-bool checkForAvailableUpdates();
+QString IsmasClient::updateOfPSAFailed(int resultCode, QString reason, QString const &version) {
+    return updateNewsToIsmas("U0003",
+                             m_progressInPercent,
+                             resultCode,
+                             "UPDATE ERROR",
+                             reason.toStdString().c_str(),
+                             version.toStdString().c_str());
+}
diff --git a/ismas/ismas_client.h b/ismas/ismas_client.h
index 7fbd5a7..fdda53d 100644
--- a/ismas/ismas_client.h
+++ b/ismas/ismas_client.h
@@ -111,7 +111,28 @@ struct PSAInstalled {
 class IsmasClient : public QObject {
     Q_OBJECT
 
+    int m_progressInPercent;
 public:
+    explicit IsmasClient() : m_progressInPercent(1) {}
+
+    enum APISM {
+        DB_PORT = 7777,
+        DIRECT_PORT = 7778
+    };
+
+    enum RESULT_CODE {
+        SUCCESS=0,
+        NO_UPDATE_NECESSARY=1,
+        BACKUP_FAILED=2,
+        WRONG_PACKAGE=3,
+        INSTALL_ERROR=4};
+
+    static std::optional<QString>
+        sendRequestReceiveResponse(int port, QString const &request);
+
+    int getProgressInPercent() const {return m_progressInPercent; }
+    void setProgressInPercent(int procent) { m_progressInPercent = procent; }
+
     QString updateNewsToIsmas(char const *event,
                               int percent,
                               int resultCode,
@@ -119,12 +140,32 @@ public:
                               char const *step_result,
                               char const *version);
 
-    QString updateOfPSAActivated();
-    QString updateOfPSASucceeded();
+    QString updateOfPSAStarted(QString const &version = QString());   // start of update process
+    QString cloneAndCheckoutCustomerRepository(QString const &info, QString const &version = QString());   // clone and checkout customer repository
+    QString checkoutBranch(QString const &info, QString const &version = QString());   // checkout branch
+    QString errorBackendNotConnected(QString const &info, QString const &version = QString());   // checkout branch
+    QString backendConnected(QString const &info, QString const &version = QString());
+    QString updateTriggerSet(QString const &info, QString const &version = QString());
+    QString errorUpdateTrigger(QString const &info, QString const &version = QString());
+    QString gitFetch(QString const &info, QString const &version = QString());
+    QString execOpkgCommand(QString const &info, QString const &version = QString());
+    QString errorGitFetch(int resultCode, QString const &info, QString const &version = QString());
+    QString updateOfPSAActivated(QString const &version = QString());
+                                    // and update accepted
+    QString updateOfPSASucceeded(QString const &version = QString()); // update process succeeded
+    QString updateOfPSAContinues(QString currentStage, QString currentStageInfo, QString const &version = QString());
+    QString updateOfPSAFailed(int resultCode, QString reason, QString const &version = QString());
+    QString sanityCheckFailed(int resultCode, QString reason, QString const &version = QString());
+
     QString updateOfPSASendVersion(PSAInstalled const &psa);
 
-    QString setUpdatesAvailable();
-    bool checkForAvailableUpdates();
+  private:
+    static void printDebugMessage(int port, QString const &clientIP, int clientPort,
+                                  QString const &message);
+    static void printInfoMessage(int port, QString const &clientIP, int clientPort,
+                                 QString const &message);
+    static void printErrorMessage(int port, QString const &clientIP, int clientPort,
+                                  QString const &message);
 };
 
 #endif // ISMAS_CLIENT_H_INCLUDED