Create m_update-object inside of constructor of worker-class:

this way the object belongs to the GUI-thread, and can be addressed via emit
by the reporting thread.

worker.cpp

@@ -166,7 +166,13 @@ Worker::Worker(int customerNr,
     // TODO: turn object into singleton
     instance = this;
     m_lastFailedUpdateStep = UPDATE_STEP::NONE;
-    m_update = nullptr;
+    m_update = new Update(this,
+                          QDir::cleanPath(m_workingDirectory + QDir::separator() + m_customerNrStr),
+                          m_customerNrStr,
+                          m_branchName,
+                          m_pluginDir,
+                          m_pluginName,
+                          m_workingDirectory);
 
     this->setObjectName("worker-object");
     QDir::setCurrent(m_workingDirectory);
@@ -175,6 +181,10 @@ Worker::Worker(int customerNr,
 }
 
 Worker::~Worker() {
+    if (m_update != nullptr) {
+        delete m_update;
+        m_update = nullptr;
+    }
 }
 
 void Worker::displayProgressInMainWindow(int progress) {
@@ -889,15 +899,7 @@ bool Worker::downloadFilesToPSAHardware() {
             QStringList lst = m_filesToDownload;
             ISMAS(lst) << (CONSOLE(lst) << UPDATE_STEP::FILES_TO_DOWNLOAD);
 
-            m_update = new Update(this,
-                                  QDir::cleanPath(m_workingDirectory + QDir::separator() + m_customerNrStr),
-                                  m_customerNrStr,
-                                  m_branchName,
-                                  m_pluginDir,
-                                  m_pluginName,
-                                  m_workingDirectory);
-
-            if (m_update->doUpdate(m_displayIndex, m_filesToDownload)) {
+            if (m_update && m_update->doUpdate(m_displayIndex, m_filesToDownload)) {
                 // prepared for use: at the moment, the dc-library does not work
                 // as expected.
 

worker.h

@@ -249,10 +249,6 @@ class Worker : public QThread{
                                      << UPDATE_STEP::SEND_LAST_VERSION));
             }
             m_worker->stopProgressLoop();
-            if (m_worker->m_update != nullptr) {
-                delete m_worker->m_update;
-                m_worker->m_update = nullptr;
-            }
             m_worker->m_updateProcessRunning = false;
             emit m_worker->enableExit();
             emit m_worker->restartExitTimer();