diff --git a/companion/src/appdata.cpp b/companion/src/appdata.cpp
index db50261df..d49f7a5af 100644
--- a/companion/src/appdata.cpp
+++ b/companion/src/appdata.cpp
@@ -735,6 +735,9 @@ AppData::AppData()
     getset( _backupOnFlash,   "backupOnFlash"           ,true  );
     getset( _checkHardwareCompatibility,   "checkHardwareCompatibility"           ,true  );
 
+    getset( _useCompanionNightlyBuilds,   "useCompanionNightlyBuilds"           ,false  );
+    getset( _useFirmwareNightlyBuilds,   "useFirmwareNightlyBuilds"           ,false  );
+
     getset( _jsSupport,       "js_support"              ,false );
     getset( _maximized,       "maximized"               ,false );
     getset( _showSplash,      "show_splash"             ,true  );
diff --git a/companion/src/appdata.h b/companion/src/appdata.h
index 27d019779..abb2b7eab 100644
--- a/companion/src/appdata.h
+++ b/companion/src/appdata.h
@@ -216,6 +216,8 @@ class AppData: protected CompStoreObj
   BOOL_PROPERTY(outputDisplayDetails, false)
   BOOL_PROPERTY(backupOnFlash, true)
   BOOL_PROPERTY(checkHardwareCompatibility, true)
+  BOOL_PROPERTY(useCompanionNightlyBuilds, false)
+  BOOL_PROPERTY(useFirmwareNightlyBuilds, false)
 
   // All the global variables
   public:
diff --git a/companion/src/apppreferencesdialog.cpp b/companion/src/apppreferencesdialog.cpp
index d84b092e3..84616e7f4 100644
--- a/companion/src/apppreferencesdialog.cpp
+++ b/companion/src/apppreferencesdialog.cpp
@@ -41,8 +41,10 @@ AppPreferencesDialog::~AppPreferencesDialog()
 
 void AppPreferencesDialog::writeValues()
 {
-  g.autoCheckApp(ui->startupCheck_companion9x->isChecked());
-  g.autoCheckFw(ui->startupCheck_fw->isChecked());
+  g.useCompanionNightlyBuilds(ui->useCompanionNightlyBuilds->isChecked());
+  g.autoCheckApp(ui->autoCheckCompanion->isChecked());
+  g.useFirmwareNightlyBuilds(ui->useFirmwareNightlyBuilds->isChecked());
+  g.autoCheckFw(ui->autoCheckFirmware->isChecked());
   g.showSplash(ui->showSplash->isChecked());
   g.simuSW(ui->simuSW->isChecked());
   g.useWizard(ui->modelWizard_CB->isChecked());
@@ -107,8 +109,10 @@ void AppPreferencesDialog::initSettings()
     ui->snapshotPath->setDisabled(true);
     ui->snapshotPathButton->setDisabled(true);
   }
-  ui->startupCheck_companion9x->setChecked(g.autoCheckApp());
-  ui->startupCheck_fw->setChecked(g.autoCheckFw());
+  ui->useCompanionNightlyBuilds->setChecked(g.useCompanionNightlyBuilds());
+  ui->autoCheckCompanion->setChecked(g.autoCheckApp());
+  ui->useFirmwareNightlyBuilds->setChecked(g.useFirmwareNightlyBuilds());
+  ui->autoCheckFirmware->setChecked(g.autoCheckFw());
   ui->showSplash->setChecked(g.showSplash());
   ui->historySize->setValue(g.historySize());
   ui->backLightColor->setCurrentIndex(g.backLight());
diff --git a/companion/src/apppreferencesdialog.ui b/companion/src/apppreferencesdialog.ui
index 2b68b6c6c..dae216aca 100644
--- a/companion/src/apppreferencesdialog.ui
+++ b/companion/src/apppreferencesdialog.ui
@@ -39,7 +39,7 @@
    <item row="0" column="0">
     <widget class="QTabWidget" name="tabWidget">
      <property name="currentIndex">
-      <number>0</number>
+      <number>1</number>
      </property>
      <widget class="QWidget" name="profileTab">
       <attribute name="title">
@@ -645,8 +645,8 @@ Mode 4:
        <string>Application Settings</string>
       </attribute>
       <layout class="QGridLayout" name="gridLayout_3">
-       <item row="7" column="1" colspan="3">
-        <widget class="QCheckBox" name="startupCheck_companion9x">
+       <item row="10" column="1" colspan="3">
+        <widget class="QCheckBox" name="autoCheckCompanion">
          <property name="text">
           <string>Automatic check for Companion updates</string>
          </property>
@@ -665,7 +665,7 @@ Mode 4:
          </property>
         </widget>
        </item>
-       <item row="10" column="1" colspan="3">
+       <item row="13" column="1" colspan="3">
         <widget class="QCheckBox" name="backupEnable">
          <property name="text">
           <string>Enable automatic backup before writing firmware</string>
@@ -679,24 +679,7 @@ Mode 4:
          </property>
         </widget>
        </item>
-       <item row="8" column="1" colspan="3">
-        <widget class="Line" name="line_2">
-         <property name="orientation">
-          <enum>Qt::Horizontal</enum>
-         </property>
-        </widget>
-       </item>
-       <item row="6" column="1" colspan="3">
-        <widget class="QCheckBox" name="startupCheck_fw">
-         <property name="text">
-          <string>Automatic check for OpenTX firmware updates</string>
-         </property>
-         <property name="checked">
-          <bool>true</bool>
-         </property>
-        </widget>
-       </item>
-       <item row="15" column="1">
+       <item row="18" column="1">
         <spacer name="verticalSpacer_2">
          <property name="orientation">
           <enum>Qt::Vertical</enum>
@@ -709,7 +692,24 @@ Mode 4:
          </property>
         </spacer>
        </item>
-       <item row="12" column="0">
+       <item row="11" column="1" colspan="3">
+        <widget class="Line" name="line_2">
+         <property name="orientation">
+          <enum>Qt::Horizontal</enum>
+         </property>
+        </widget>
+       </item>
+       <item row="8" column="1" colspan="3">
+        <widget class="QCheckBox" name="autoCheckFirmware">
+         <property name="text">
+          <string>Automatic check for OpenTX firmware updates</string>
+         </property>
+         <property name="checked">
+          <bool>true</bool>
+         </property>
+        </widget>
+       </item>
+       <item row="15" column="0">
         <widget class="QLabel" name="label_10">
          <property name="sizePolicy">
           <sizepolicy hsizetype="Preferred" vsizetype="Minimum">
@@ -749,7 +749,7 @@ Mode 4:
          </property>
         </widget>
        </item>
-       <item row="13" column="0">
+       <item row="16" column="0">
         <widget class="QLabel" name="label_9">
          <property name="sizePolicy">
           <sizepolicy hsizetype="Preferred" vsizetype="Minimum">
@@ -784,14 +784,14 @@ Mode 4:
          </property>
         </widget>
        </item>
-       <item row="9" column="0">
+       <item row="12" column="0">
         <widget class="QLabel" name="label_17">
          <property name="text">
           <string>Automatic Backup Folder</string>
          </property>
         </widget>
        </item>
-       <item row="11" column="1" colspan="3">
+       <item row="14" column="1" colspan="3">
         <widget class="Line" name="line_5">
          <property name="orientation">
           <enum>Qt::Horizontal</enum>
@@ -805,7 +805,7 @@ Mode 4:
          </property>
         </widget>
        </item>
-       <item row="13" column="1">
+       <item row="16" column="1">
         <widget class="QLineEdit" name="libraryPath">
          <property name="enabled">
           <bool>true</bool>
@@ -815,7 +815,7 @@ Mode 4:
          </property>
         </widget>
        </item>
-       <item row="12" column="1">
+       <item row="15" column="1">
         <widget class="QComboBox" name="splashincludeCB">
          <property name="sizePolicy">
           <sizepolicy hsizetype="Expanding" vsizetype="Fixed">
@@ -835,7 +835,7 @@ Mode 4:
          </item>
         </widget>
        </item>
-       <item row="9" column="1">
+       <item row="12" column="1">
         <widget class="QLineEdit" name="backupPath">
          <property name="minimumSize">
           <size>
@@ -848,7 +848,7 @@ Mode 4:
          </property>
         </widget>
        </item>
-       <item row="9" column="2" colspan="2">
+       <item row="12" column="2" colspan="2">
         <widget class="QPushButton" name="backupPathButton">
          <property name="text">
           <string>Open Folder</string>
@@ -875,13 +875,33 @@ Mode 4:
          </property>
         </widget>
        </item>
-       <item row="13" column="2" colspan="2">
+       <item row="16" column="2" colspan="2">
         <widget class="QPushButton" name="libraryPathButton">
          <property name="text">
           <string>Open Folder</string>
          </property>
         </widget>
        </item>
+       <item row="6" column="1">
+        <widget class="QCheckBox" name="useFirmwareNightlyBuilds">
+         <property name="text">
+          <string>Use OpenTX firmware nightly builds</string>
+         </property>
+         <property name="checked">
+          <bool>false</bool>
+         </property>
+        </widget>
+       </item>
+       <item row="9" column="1">
+        <widget class="QCheckBox" name="useCompanionNightlyBuilds">
+         <property name="text">
+          <string>Use Companion nightly builds</string>
+         </property>
+         <property name="checked">
+          <bool>false</bool>
+         </property>
+        </widget>
+       </item>
       </layout>
      </widget>
      <widget class="QWidget" name="simulatorTab">
@@ -1112,8 +1132,8 @@ Mode 4:
   <tabstop>historySize</tabstop>
   <tabstop>showSplash</tabstop>
   <tabstop>modelWizard_CB</tabstop>
-  <tabstop>startupCheck_fw</tabstop>
-  <tabstop>startupCheck_companion9x</tabstop>
+  <tabstop>autoCheckFirmware</tabstop>
+  <tabstop>autoCheckCompanion</tabstop>
   <tabstop>backupPath</tabstop>
   <tabstop>backupPathButton</tabstop>
   <tabstop>backupEnable</tabstop>
diff --git a/companion/src/firmwares/opentx/opentxinterface.cpp b/companion/src/firmwares/opentx/opentxinterface.cpp
index 5913a5446..744223f65 100644
--- a/companion/src/firmwares/opentx/opentxinterface.cpp
+++ b/companion/src/firmwares/opentx/opentxinterface.cpp
@@ -1048,7 +1048,7 @@ bool OpenTxEepromInterface::loadBackup(RadioData &radioData, uint8_t *eeprom, in
 
 QString OpenTxFirmware::getFirmwareUrl()
 {
-  QString url = OPENTX_FIRMWARE_DOWNLOADS;
+  QString url = (g.useFirmwareNightlyBuilds() ? OPENTX_NIGHT_FIRMWARE_DOWNLOADS : OPENTX_FIRMWARE_DOWNLOADS);
   switch (board) {
     case BOARD_STOCK:
     case BOARD_M128:
@@ -1072,16 +1072,16 @@ QString OpenTxFirmware::getFirmwareUrl()
 
 QString OpenTxFirmware::getReleaseNotesUrl()
 {
-  QString url = OPENTX_FIRMWARE_DOWNLOADS;
+  QString url = (g.useFirmwareNightlyBuilds() ? OPENTX_NIGHT_FIRMWARE_DOWNLOADS : OPENTX_FIRMWARE_DOWNLOADS);
   url.append("/releasenotes.txt");
   return url;
 }
 
 QString OpenTxFirmware::getStampUrl()
 {
-   QString url = OPENTX_FIRMWARE_DOWNLOADS;
-   url.append("/stamp-opentx.txt");
-   return url;
+  QString url = (g.useFirmwareNightlyBuilds() ? OPENTX_NIGHT_FIRMWARE_DOWNLOADS : OPENTX_FIRMWARE_DOWNLOADS);
+  url.append("/stamp-opentx.txt");
+  return url;
 }
 
 void addOpenTxCommonOptions(OpenTxFirmware * firmware)
diff --git a/companion/src/firmwares/opentx/opentxinterface.h b/companion/src/firmwares/opentx/opentxinterface.h
index aa2a2e512..e43d7cbcb 100644
--- a/companion/src/firmwares/opentx/opentxinterface.h
+++ b/companion/src/firmwares/opentx/opentxinterface.h
@@ -19,7 +19,8 @@
 
 #include "eeprominterface.h"
 
-#define OPENTX_FIRMWARE_DOWNLOADS    "http://downloads-21.open-tx.org/firmware"
+#define OPENTX_FIRMWARE_DOWNLOADS        "http://downloads-21.open-tx.org/firmware"
+#define OPENTX_NIGHT_FIRMWARE_DOWNLOADS  "http://downloads-21.open-tx.org/nightly/firmware"
 
 class RleFile;
 
diff --git a/companion/src/helpers.cpp b/companion/src/helpers.cpp
index 754d849a0..49b2ed865 100644
--- a/companion/src/helpers.cpp
+++ b/companion/src/helpers.cpp
@@ -1017,27 +1017,36 @@ QPixmap makePixMap( QImage image, QString firmwareType )
   return(QPixmap::fromImage(image));
 }
 
-int version2index(QString version)
+int version2index(const QString & version)
 {
-  QStringList parts = version.split('.');
-  int result = 0;
-  if (parts.size() > 2)
-    result = parts[2].toInt();
+  int result = 999;
+  QStringList parts = version.split(":n");
   if (parts.size() > 1)
-    result += 100 * parts[1].toInt();
+    result = parts[1].toInt(); // nightly build
+  parts = parts[0].split('.');
+  if (parts.size() > 2)
+    result += 1000 * parts[2].toInt();
+  if (parts.size() > 1)
+    result += 100000 * parts[1].toInt();
   if (parts.size() > 0)
-    result += 10000 * parts[0].toInt();
+    result += 10000000 * parts[0].toInt();
   return result;
 }
 
 QString index2version(int index)
 {
-  if (index >= 19900) {
+  if (index >= 19900000) {
+    int nightly = index % 1000;
+    index /= 1000;
     int revision = index % 100;
     index /= 100;
     int minor = index % 100;
     int major = index / 100;
-    return QString("%1.%2.%3").arg(major).arg(minor).arg(revision);
+    QString result = QString("%1.%2.%3").arg(major).arg(minor).arg(revision);
+    if (nightly > 0 && nightly < 999) {
+      result += QString(":n%1").arg(nightly);
+    }
+    return result;
   }
   else {
     return QString();
diff --git a/companion/src/helpers.h b/companion/src/helpers.h
index 69d5d56c6..5e3c40503 100644
--- a/companion/src/helpers.h
+++ b/companion/src/helpers.h
@@ -162,7 +162,7 @@ QVector<T> findWidgets(QObject * object, const QString & name)
 // Format a pixmap to fit on the radio using a specific firmware
 QPixmap makePixMap( QImage image, QString firmwareType );
 
-int version2index(QString version);
+int version2index(const QString & version);
 QString index2version(int index);
 
 class QTimeS : public QTime
diff --git a/companion/src/mainwindow.cpp b/companion/src/mainwindow.cpp
index 8231c3ba7..6688efbe7 100644
--- a/companion/src/mainwindow.cpp
+++ b/companion/src/mainwindow.cpp
@@ -70,15 +70,16 @@
 #include "radiointerface.h"
 #include "progressdialog.h"
 
-#define OPENTX_COMPANION_DOWNLOADS   "http://downloads-21.open-tx.org/companion"
-#define DONATE_STR      "https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=QUZ48K4SEXDP2"
+#define OPENTX_COMPANION_DOWNLOADS        "http://downloads-21.open-tx.org/companion"
+#define OPENTX_NIGHT_COMPANION_DOWNLOADS  "http://downloads-21.open-tx.org/nightly/companion"
+#define DONATE_STR                        "https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=QUZ48K4SEXDP2"
 
 #ifdef __APPLE__
-  #define C9X_STAMP     OPENTX_COMPANION_DOWNLOADS "/companion-macosx.stamp"
-  #define C9X_INSTALLER "/companion-macosx-%1.dmg"
+  #define COMPANION_STAMP                 "companion-macosx.stamp"
+  #define COMPANION_INSTALLER             "companion-macosx-%1.dmg"
 #else
-  #define C9X_STAMP     OPENTX_COMPANION_DOWNLOADS "/companion-windows.stamp"
-  #define C9X_INSTALLER "/companion-windows-%1.exe"
+  #define COMPANION_STAMP                 "companion-windows.stamp"
+  #define COMPANION_INSTALLER             "companion-windows-%1.exe"
 #endif
 
 #if defined WIN32 || !defined __GNUC__
@@ -228,7 +229,7 @@ void MainWindow::checkForUpdates()
     // TODO why create each time a network manager?
     networkManager = new QNetworkAccessManager(this);
     connect(networkManager, SIGNAL(finished(QNetworkReply*)),this, SLOT(checkForCompanionUpdateFinished(QNetworkReply*)));
-    QNetworkRequest request(QUrl(C9X_STAMP));
+    QNetworkRequest request(QUrl(QString("%1/%2").arg(g.useCompanionNightlyBuilds() ? OPENTX_NIGHT_COMPANION_DOWNLOADS : OPENTX_COMPANION_DOWNLOADS).arg(COMPANION_STAMP)));
     request.setAttribute(QNetworkRequest::CacheLoadControlAttribute, QNetworkRequest::AlwaysNetwork);
     networkManager->get(request);
   }
@@ -289,13 +290,13 @@ void MainWindow::checkForCompanionUpdateFinished(QNetworkReply * reply)
 
         if (ret == QMessageBox::Yes) {
 #if defined __APPLE__          
-          QString fileName = QFileDialog::getSaveFileName(this, tr("Save As"), g.updatesDir() + QString(C9X_INSTALLER).arg(version));
+          QString fileName = QFileDialog::getSaveFileName(this, tr("Save As"), g.updatesDir() + QString(COMPANION_INSTALLER).arg(version));
 #else            
-          QString fileName = QFileDialog::getSaveFileName(this, tr("Save As"), g.updatesDir() + QString(C9X_INSTALLER).arg(version), tr("Executable (*.exe)"));
+          QString fileName = QFileDialog::getSaveFileName(this, tr("Save As"), g.updatesDir() + QString(COMPANION_INSTALLER).arg(version), tr("Executable (*.exe)"));
 #endif
           if (!fileName.isEmpty()) {
             g.updatesDir(QFileInfo(fileName).dir().absolutePath());
-            downloadDialog * dd = new downloadDialog(this, QString(OPENTX_COMPANION_DOWNLOADS C9X_INSTALLER).arg(version), fileName);
+            downloadDialog * dd = new downloadDialog(this, QString("%1/%2").arg(g.useCompanionNightlyBuilds() ? OPENTX_NIGHT_COMPANION_DOWNLOADS : OPENTX_COMPANION_DOWNLOADS).arg(QString(COMPANION_INSTALLER).arg(version)), fileName);
             installer_fileName = fileName;
             connect(dd, SIGNAL(accepted()), this, SLOT(updateDownloaded()));
             dd->exec();