diff --git a/UpdatePTUDevCtrl/update.cpp b/UpdatePTUDevCtrl/update.cpp
index bcda1f7..7116e7f 100644
--- a/UpdatePTUDevCtrl/update.cpp
+++ b/UpdatePTUDevCtrl/update.cpp
@@ -711,6 +711,112 @@ bool Update::checkDownloadedJsonVersions(QStringList const& jsonFileNames) {
     return false;
 }
 
+QMap<QString, QString>
+Update::getInstalledJsonVersions(QStringList const& jsonFileNames) {
+    QMap<QString, QString> map;
+
+    if (!m_hw) {
+        qCritical() << "(" << __func__ << ":" << __LINE__ << "):"
+                    << "ERROR!!! m_hw == nullptr";
+        return map;
+    }
+
+    int tries = 20;
+    while ((m_sys_areDCdataValid = m_hw->sys_areDCdataValid()) == false) {
+        // must deliver 'true', only then are all data from hwapi valid
+        if (--tries < 0) {
+            qCritical() << "(" << __func__ << ":" << __LINE__ << "):"
+                        << "ERROR!!! DC DATA NOT VALID -> CA-SLAVE-PLUGIN NOT CONNECTED";
+            return map;
+        }
+        qCritical() << "(" << __func__ << ":" << __LINE__ << "):"
+                    << "ERROR!!! DC DATA NOT VALID -> CA-SLAVE-PLUGIN NOT CONNECTED (" << tries << ")";
+        m_hw->dc_autoRequest(true);
+        QThread::msleep(500);
+    }
+
+    for (QStringList::size_type i=0; i < jsonFileNames.size(); ++i) {
+
+        uint8_t jsonNr = 0;
+
+        QString const &fName = jsonFileNames[i];
+
+        // send one request for every single version
+        // jsonNr=1...36, 1=config file (cust.Nr) 2=devices  3=cash  4=res.
+        //      6=printer template 1 ..... 36= template 32
+
+        if (fName.endsWith("conf.json")) {
+            jsonNr = 1;
+        } else
+        if (fName.endsWith("device.json")) {
+            jsonNr = 2;
+        } else
+        if (fName.endsWith("cash.json")) {
+            jsonNr = 3;
+        } else {
+            QRegularExpressionMatch match;
+            static const QRegularExpression re("^(.*print)([0-3][0-9])\\.json\\s*$");
+            int idx = fName.indexOf(re, 0, &match);
+            if (idx != -1) {
+                QString captured = match.captured(match.lastCapturedIndex());
+                bool ok = false;
+                int n = captured.toInt(&ok);
+                if (ok) {
+                    // note: use 5 (instead of 4 -> index has been shifted)
+                    jsonNr = n + 5;
+                }
+            }
+        }
+
+        if (jsonNr != 0) {
+            // send one request for every single version
+            // jsonNr=1...36, 1=config file (cust.Nr) 2=devices  3=cash  4=res.
+            //      5=printer template 1 ..... 36= template 32
+
+            m_hw->sys_requestJsonVersions(jsonNr);
+            QThread::msleep(500);
+
+            char buf[64];
+            memset(buf, 0x00, sizeof(buf));
+            m_hw->sys_getJsonVersions(jsonNr, buf);
+            buf[16] = '\0'; // the DC only handles 16 bytes
+
+            static const QByteArray cb(16, (char)0xff);
+
+            QString const installedVersion(QString::fromStdString(buf));
+            QString const fileVersion = getFileVersion(jsonFileNames[i]);
+
+            QFileInfo fi(jsonFileNames[i]);
+
+            if (cb == QByteArray(buf)) {
+                map.insert(fi.fileName(), "inst.vers.not.avail");
+            } else {
+                map.insert(fi.fileName(), installedVersion);
+            }
+
+            qCritical() << endl;
+            qCritical() << "                json request nr:" << jsonNr;
+
+            if (installedVersion == fileVersion) {
+                qCritical() << "                      json file:" << fi.fileName();
+                qCritical() << "        installed version in DC:" << installedVersion;
+            } else
+            if (cb == QByteArray(buf) && fileVersion == "") {
+                qCritical() << "unknown json file (repo and DC):" << fi.fileName();
+            } else {
+                qCritical() << "                      json file:" << fi.fileName();
+                qCritical() << "        installed version in DC:" << installedVersion;
+                qCritical() << "     file version in repository:" << fileVersion;
+            }
+
+        } else {
+            qCritical() << "CANNOT FIND JSON-NR FOR" << fName;
+        }
+    }
+
+    return map;
+}
+
 bool Update::doUpdate(int &displayIndex, QStringList const &filesToWorkOn) {
 
     if (!m_hw) {