diff --git a/src/lib/app/mainapplication.cpp b/src/lib/app/mainapplication.cpp
--- a/src/lib/app/mainapplication.cpp
+++ b/src/lib/app/mainapplication.cpp
@@ -974,6 +974,10 @@
     webSettings->setAttribute(QWebEngineSettings::DnsPrefetchEnabled, settings.value(QSL("DNSPrefetch"), true).toBool());
 #endif
 
+#if QTWEBENGINEWIDGETS_VERSION >= QT_VERSION_CHECK(5, 13, 0)
+    webSettings->setAttribute(QWebEngineSettings::PdfViewerEnabled, settings.value(QSL("intPDFViewer"), false).toBool());
+#endif
+
     webSettings->setDefaultTextEncoding(settings.value(QSL("DefaultEncoding"), webSettings->defaultTextEncoding()).toString());
 
     setWheelScrollLines(settings.value(QSL("wheelScrollLines"), wheelScrollLines()).toInt());
diff --git a/src/lib/preferences/preferences.h b/src/lib/preferences/preferences.h
--- a/src/lib/preferences/preferences.h
+++ b/src/lib/preferences/preferences.h
@@ -74,6 +74,7 @@
     void setManualProxyConfigurationEnabled(bool state);
     void useExternalDownManagerChanged(bool state);
     void changeCachePathClicked();
+    void allowPluginsToggled(bool checked);
 
     void newTabChanged(int value);
     void afterLaunchChanged(int value);
diff --git a/src/lib/preferences/preferences.cpp b/src/lib/preferences/preferences.cpp
--- a/src/lib/preferences/preferences.cpp
+++ b/src/lib/preferences/preferences.cpp
@@ -121,6 +121,10 @@
     ui->dnsPrefetch->setVisible(false);
 #endif
 
+#if QTWEBENGINEWIDGETS_VERSION < QT_VERSION_CHECK(5, 13, 0)
+    ui->intPDFViewer->setVisible(false);
+#endif
+
     auto setCategoryIcon = [this](int index, const QIcon &icon) {
         ui->listWidget->item(index)->setIcon(QIcon(icon.pixmap(32)));
     };
@@ -284,6 +288,7 @@
     // BROWSING
     settings.beginGroup("Web-Browser-Settings");
     ui->allowPlugins->setChecked(settings.value("allowPlugins", true).toBool());
+    connect(ui->allowPlugins, &QAbstractButton::toggled, this, &Preferences::allowPluginsToggled);
     ui->allowJavaScript->setChecked(settings.value("allowJavaScript", true).toBool());
     ui->linksInFocusChain->setChecked(settings.value("IncludeLinkInFocusChain", false).toBool());
     ui->spatialNavigation->setChecked(settings.value("SpatialNavigation", false).toBool());
@@ -295,6 +300,8 @@
     ui->disableVideoAutoPlay->setChecked(settings.value("DisableVideoAutoPlay", false).toBool());
     ui->webRTCPublicIpOnly->setChecked(settings.value("WebRTCPublicIpOnly", true).toBool());
     ui->dnsPrefetch->setChecked(settings.value("DNSPrefetch", true).toBool());
+    ui->intPDFViewer->setChecked(settings.value("intPDFViewer", false).toBool());
+    ui->intPDFViewer->setEnabled(ui->allowPlugins->isChecked());
 
     const auto levels = WebView::zoomLevels();
     for (int level : levels) {
@@ -539,6 +546,11 @@
     QzTools::setWmClass("Preferences", this);
 }
 
+void Preferences::allowPluginsToggled(bool checked)
+{
+    ui->intPDFViewer->setEnabled(checked);
+}
+
 void Preferences::chooseExternalDownloadManager()
 {
     QString path = QzTools::getOpenFileName("Preferences-ExternalDownloadManager", this, tr("Choose executable location..."), QDir::homePath());
@@ -959,6 +971,7 @@
     settings.setValue("DisableVideoAutoPlay", ui->disableVideoAutoPlay->isChecked());
     settings.setValue("WebRTCPublicIpOnly", ui->webRTCPublicIpOnly->isChecked());
     settings.setValue("DNSPrefetch", ui->dnsPrefetch->isChecked());
+    settings.setValue("intPDFViewer", ui->intPDFViewer->isChecked());
 
 #ifdef Q_OS_WIN
     settings.setValue("CheckDefaultBrowser", ui->checkDefaultBrowser->isChecked());
diff --git a/src/lib/preferences/preferences.ui b/src/lib/preferences/preferences.ui
--- a/src/lib/preferences/preferences.ui
+++ b/src/lib/preferences/preferences.ui
@@ -1008,7 +1008,14 @@
                  <item>
                   <widget class="QCheckBox" name="allowPlugins">
                    <property name="text">
-                    <string>Allow Pepper Plugins (Flash plugin)</string>
+                    <string>Enable Pepper plugin API (PPAPI)</string>
+                   </property>
+                  </widget>
+                 </item>
+                 <item>
+                  <widget class="QCheckBox" name="intPDFViewer">
+                   <property name="text">
+                    <string>Use built-in PDF viewer (requires PPAPI)</string>
                    </property>
                   </widget>
                  </item>