diff --git a/source/backend/engine/CarlaEngineJack.cpp b/source/backend/engine/CarlaEngineJack.cpp
index e774fc4ed..9efd37d77 100644
--- a/source/backend/engine/CarlaEngineJack.cpp
+++ b/source/backend/engine/CarlaEngineJack.cpp
@@ -1854,7 +1854,7 @@ private:
                 if (thisPortId == -1)
                     continue;
 
-                if (const char** connections = jackbridge_port_get_connections(jackPort))
+                if (const char** connections = jackbridge_port_get_all_connections(jackPort))
                 {
                     for (int j=0; connections[j] != nullptr; ++j)
                     {
@@ -1869,7 +1869,7 @@ private:
                     jackbridge_free(connections);
                 }
                 else
-                    carla_stderr("jack_port_get_connections failed for port %s", fullPortName);
+                    carla_stderr("jack_port_get_all_connections failed for port %s", fullPortName);
             }
 
             jackbridge_free(ports);
diff --git a/source/backend/standalone/CarlaStandalone.cpp b/source/backend/standalone/CarlaStandalone.cpp
index afe3e157b..820df6973 100644
--- a/source/backend/standalone/CarlaStandalone.cpp
+++ b/source/backend/standalone/CarlaStandalone.cpp
@@ -663,6 +663,10 @@ void carla_set_engine_option(EngineOption option, int value, const char* valueSt
 
     case CB::ENGINE_OPTION_AUDIO_DEVICE:
         CARLA_SAFE_ASSERT_RETURN(valueStr != nullptr && valueStr[0] != '\0',);
+
+        if (gStandalone.engineOptions.audioDevice != nullptr)
+            delete[] gStandalone.engineOptions.audioDevice;
+
         gStandalone.engineOptions.audioDevice = valueStr;
         break;
 
diff --git a/source/carla-patchbay b/source/carla-patchbay
index 8a9776956..3176ba95b 100755
--- a/source/carla-patchbay
+++ b/source/carla-patchbay
@@ -75,7 +75,7 @@ if __name__ == '__main__':
     Carla.isControl   = False
     Carla.isLocal     = True
     Carla.isPlugin    = False
-    Carla.processMode = PROCESS_MODE_MULTIPLE_CLIENTS
+    Carla.processMode = ENGINE_PROCESS_MODE_MULTIPLE_CLIENTS
 
     initHost(appName, libPrefix)
 
diff --git a/source/carla-rack b/source/carla-rack
index d9ac629c3..7c47795da 100755
--- a/source/carla-rack
+++ b/source/carla-rack
@@ -75,7 +75,7 @@ if __name__ == '__main__':
     Carla.isControl   = False
     Carla.isLocal     = True
     Carla.isPlugin    = False
-    Carla.processMode = PROCESS_MODE_CONTINUOUS_RACK
+    Carla.processMode = ENGINE_PROCESS_MODE_CONTINUOUS_RACK
 
     initHost(appName, libPrefix)
 
diff --git a/source/carla_host.py b/source/carla_host.py
index 811d14421..bcbfa8698 100644
--- a/source/carla_host.py
+++ b/source/carla_host.py
@@ -24,7 +24,7 @@
     #from PyQt5.QtGui import QPalette
     #from PyQt5.QtWidgets import QApplication, QFileSystemModel, QMainWindow
 #except:
-from PyQt4.QtCore import QModelIndex, QTimer
+from PyQt4.QtCore import qCritical, QModelIndex, QTimer
 from PyQt4.QtGui import QApplication, QFileSystemModel, QMainWindow, QPalette
 
 # ------------------------------------------------------------------------------------------------------------
@@ -220,7 +220,7 @@ class HostWindow(QMainWindow):
         # Set up GUI (right panel)
 
         self.fDirModel = QFileSystemModel(self)
-        self.fDirModel.setNameFilters(cString(Carla.host.get_supported_file_types()).split(";"))
+        self.fDirModel.setNameFilters(charPtrToString(Carla.host.get_supported_file_extensions()).split(";"))
         self.fDirModel.setRootPath(HOME)
 
         self.ui.fileTreeView.setModel(self.fDirModel)
@@ -357,33 +357,33 @@ class HostWindow(QMainWindow):
 
         if audioDriver == "JACK":
             #transportMode  = settings.value("Engine/TransportMode",       TRANSPORT_MODE_JACK,                 type=int)
-            transportMode   = TRANSPORT_MODE_JACK
+            transportMode   = ENGINE_TRANSPORT_MODE_JACK
         else:
-            transportMode   = TRANSPORT_MODE_INTERNAL
+            transportMode   = ENGINE_TRANSPORT_MODE_INTERNAL
             audioNumPeriods = settings.value("Engine/AudioBufferSize", CARLA_DEFAULT_AUDIO_NUM_PERIODS, type=int)
             audioBufferSize = settings.value("Engine/AudioBufferSize", CARLA_DEFAULT_AUDIO_BUFFER_SIZE, type=int)
             audioSampleRate = settings.value("Engine/AudioSampleRate", CARLA_DEFAULT_AUDIO_SAMPLE_RATE, type=int)
             audioDevice     = settings.value("Engine/AudioDevice",     "",                              type=str)
 
-            Carla.host.set_engine_option(OPTION_AUDIO_NUM_PERIODS, audioNumPeriods, "")
-            Carla.host.set_engine_option(OPTION_AUDIO_BUFFER_SIZE, audioBufferSize, "")
-            Carla.host.set_engine_option(OPTION_AUDIO_SAMPLE_RATE, audioSampleRate, "")
-            Carla.host.set_engine_option(OPTION_AUDIO_DEVICE,   0, audioDevice)
+            Carla.host.set_engine_option(ENGINE_OPTION_AUDIO_NUM_PERIODS, audioNumPeriods, "")
+            Carla.host.set_engine_option(ENGINE_OPTION_AUDIO_BUFFER_SIZE, audioBufferSize, "")
+            Carla.host.set_engine_option(ENGINE_OPTION_AUDIO_SAMPLE_RATE, audioSampleRate, "")
+            Carla.host.set_engine_option(ENGINE_OPTION_AUDIO_DEVICE,   0, audioDevice)
 
-        if Carla.processMode == PROCESS_MODE_CONTINUOUS_RACK:
+        if Carla.processMode == ENGINE_PROCESS_MODE_CONTINUOUS_RACK:
             forceStereo = True
-        elif Carla.processMode == PROCESS_MODE_MULTIPLE_CLIENTS and LADISH_APP_NAME:
+        elif Carla.processMode == ENGINE_PROCESS_MODE_MULTIPLE_CLIENTS and LADISH_APP_NAME:
             print("LADISH detected but using multiple clients (not allowed), forcing single client now")
-            Carla.processMode = PROCESS_MODE_SINGLE_CLIENT
+            Carla.processMode = ENGINE_PROCESS_MODE_SINGLE_CLIENT
 
-        Carla.host.set_engine_option(OPTION_FORCE_STEREO,          forceStereo,         "")
-        Carla.host.set_engine_option(OPTION_PREFER_PLUGIN_BRIDGES, preferPluginBridges, "")
-        Carla.host.set_engine_option(OPTION_PREFER_UI_BRIDGES,     preferUiBridges,     "")
-        Carla.host.set_engine_option(OPTION_UIS_ALWAYS_ON_TOP,     uisAlwaysOnTop,      "")
-        Carla.host.set_engine_option(OPTION_UI_BRIDGES_TIMEOUT,    uiBridgesTimeout,    "")
-        Carla.host.set_engine_option(OPTION_PROCESS_MODE,          Carla.processMode,   "")
-        Carla.host.set_engine_option(OPTION_MAX_PARAMETERS,        Carla.maxParameters, "")
-        Carla.host.set_engine_option(OPTION_TRANSPORT_MODE,        transportMode,       "")
+        Carla.host.set_engine_option(ENGINE_OPTION_FORCE_STEREO,          forceStereo,         "")
+        Carla.host.set_engine_option(ENGINE_OPTION_PREFER_PLUGIN_BRIDGES, preferPluginBridges, "")
+        Carla.host.set_engine_option(ENGINE_OPTION_PREFER_UI_BRIDGES,     preferUiBridges,     "")
+        Carla.host.set_engine_option(ENGINE_OPTION_UIS_ALWAYS_ON_TOP,     uisAlwaysOnTop,      "")
+        Carla.host.set_engine_option(ENGINE_OPTION_UI_BRIDGES_TIMEOUT,    uiBridgesTimeout,    "")
+        Carla.host.set_engine_option(ENGINE_OPTION_PROCESS_MODE,          Carla.processMode,   "")
+        Carla.host.set_engine_option(ENGINE_OPTION_MAX_PARAMETERS,        Carla.maxParameters, "")
+        Carla.host.set_engine_option(ENGINE_OPTION_TRANSPORT_MODE,        transportMode,       "")
 
         return audioDriver
 
@@ -395,7 +395,7 @@ class HostWindow(QMainWindow):
                 #self.fFirstEngineInit = False
                 #return
 
-            audioError = cString(Carla.host.get_last_error())
+            audioError = Carla.host.get_last_error()
 
             if audioError:
                 QMessageBox.critical(self, self.tr("Error"), self.tr("Could not connect to Audio backend '%s', possible reasons:\n%s" % (audioDriver, audioError)))
@@ -425,7 +425,7 @@ class HostWindow(QMainWindow):
             self.fContainer.removeAllPlugins()
 
         if Carla.host.is_engine_running() and not Carla.host.engine_close():
-            print(cString(Carla.host.get_last_error()))
+            print(Carla.host.get_last_error())
 
         self.fBufferSize = 0
         self.fSampleRate = 0.0
@@ -441,7 +441,7 @@ class HostWindow(QMainWindow):
     # -----------------------------------------------------------------
     # Internal stuff (plugins)
 
-    def getExtraStuff(self, plugin):
+    def getExtraPtr(self, plugin):
         ptype = plugin['type']
 
         if ptype == PLUGIN_LADSPA:
@@ -461,7 +461,7 @@ class HostWindow(QMainWindow):
                 addr = addressof(int1)
                 return cast(addr, INTPOINTER)
 
-        return c_nullptr
+        return None
 
     def maybeLoadRDFs(self):
         if not self.fLadspaRdfNeedsUpdate:
@@ -783,10 +783,10 @@ class HostWindow(QMainWindow):
         ptype    = dialog.fRetPlugin['type']
         filename = dialog.fRetPlugin['binary']
         label    = dialog.fRetPlugin['label']
-        extraStuff = self.getExtraStuff(dialog.fRetPlugin)
+        extraPtr = self.getExtraPtr(dialog.fRetPlugin)
 
-        if not Carla.host.add_plugin(btype, ptype, filename, None, label, c_nullptr):
-            CustomMessageBox(self, QMessageBox.Critical, self.tr("Error"), self.tr("Failed to load plugin"), cString(Carla.host.get_last_error()), QMessageBox.Ok, QMessageBox.Ok)
+        if not Carla.host.add_plugin(btype, ptype, filename, None, label, extraPtr):
+            CustomMessageBox(self, QMessageBox.Critical, self.tr("Error"), self.tr("Failed to load plugin"), charPtrToString(Carla.host.get_last_error()), QMessageBox.Ok, QMessageBox.Ok)
             return
 
     @pyqtSlot()
@@ -895,7 +895,7 @@ class HostWindow(QMainWindow):
         if not Carla.host.load_filename(filename):
             CustomMessageBox(self, QMessageBox.Critical, self.tr("Error"),
                              self.tr("Failed to load file"),
-                             cString(Carla.host.get_last_error()), QMessageBox.Ok, QMessageBox.Ok)
+                             Carla.host.get_last_error(), QMessageBox.Ok, QMessageBox.Ok)
 
     # -----------------------------------------------------------------
 
@@ -1018,77 +1018,77 @@ def EngineCallback(ptr, action, pluginId, value1, value2, value3, valueStr):
     if pluginId < 0 or not Carla.gui:
         return
 
-    if action == CALLBACK_DEBUG:
-        Carla.gui.DebugCallback.emit(pluginId, value1, value2, value3, cString(valueStr))
-    elif action == CALLBACK_PLUGIN_ADDED:
+    if action == ENGINE_CALLBACK_DEBUG:
+        Carla.gui.DebugCallback.emit(pluginId, value1, value2, value3, charPtrToString(valueStr))
+    elif action == ENGINE_CALLBACK_PLUGIN_ADDED:
         Carla.gui.PluginAddedCallback.emit(pluginId)
-    elif action == CALLBACK_PLUGIN_REMOVED:
+    elif action == ENGINE_CALLBACK_PLUGIN_REMOVED:
         Carla.gui.PluginRemovedCallback.emit(pluginId)
-    elif action == CALLBACK_PLUGIN_RENAMED:
+    elif action == ENGINE_CALLBACK_PLUGIN_RENAMED:
         Carla.gui.PluginRenamedCallback.emit(pluginId, valueStr)
-    elif action == CALLBACK_PARAMETER_VALUE_CHANGED:
+    elif action == ENGINE_CALLBACK_PARAMETER_VALUE_CHANGED:
         Carla.gui.ParameterValueChangedCallback.emit(pluginId, value1, value3)
-    elif action == CALLBACK_PARAMETER_DEFAULT_CHANGED:
+    elif action == ENGINE_CALLBACK_PARAMETER_DEFAULT_CHANGED:
         Carla.gui.ParameterDefaultChangedCallback.emit(pluginId, value1, value3)
-    elif action == CALLBACK_PARAMETER_MIDI_CHANNEL_CHANGED:
+    elif action == ENGINE_CALLBACK_PARAMETER_MIDI_CHANNEL_CHANGED:
         Carla.gui.ParameterMidiChannelChangedCallback.emit(pluginId, value1, value2)
-    elif action == CALLBACK_PARAMETER_MIDI_CC_CHANGED:
+    elif action == ENGINE_CALLBACK_PARAMETER_MIDI_CC_CHANGED:
         Carla.gui.ParameterMidiCcChangedCallback.emit(pluginId, value1, value2)
-    elif action == CALLBACK_PROGRAM_CHANGED:
+    elif action == ENGINE_CALLBACK_PROGRAM_CHANGED:
         Carla.gui.ProgramChangedCallback.emit(pluginId, value1)
-    elif action == CALLBACK_MIDI_PROGRAM_CHANGED:
+    elif action == ENGINE_CALLBACK_MIDI_PROGRAM_CHANGED:
         Carla.gui.MidiProgramChangedCallback.emit(pluginId, value1)
-    elif action == CALLBACK_NOTE_ON:
+    elif action == ENGINE_CALLBACK_NOTE_ON:
         Carla.gui.NoteOnCallback.emit(pluginId, value1, value2, value3)
-    elif action == CALLBACK_NOTE_OFF:
+    elif action == ENGINE_CALLBACK_NOTE_OFF:
         Carla.gui.NoteOffCallback.emit(pluginId, value1, value2)
-    elif action == CALLBACK_SHOW_GUI:
+    elif action == ENGINE_CALLBACK_UI_STATE_CHANGED:
         Carla.gui.ShowGuiCallback.emit(pluginId, value1)
-    elif action == CALLBACK_UPDATE:
+    elif action == ENGINE_CALLBACK_UPDATE:
         Carla.gui.UpdateCallback.emit(pluginId)
-    elif action == CALLBACK_RELOAD_INFO:
+    elif action == ENGINE_CALLBACK_RELOAD_INFO:
         Carla.gui.ReloadInfoCallback.emit(pluginId)
-    elif action == CALLBACK_RELOAD_PARAMETERS:
+    elif action == ENGINE_CALLBACK_RELOAD_PARAMETERS:
         Carla.gui.ReloadParametersCallback.emit(pluginId)
-    elif action == CALLBACK_RELOAD_PROGRAMS:
+    elif action == ENGINE_CALLBACK_RELOAD_PROGRAMS:
         Carla.gui.ReloadProgramsCallback.emit(pluginId)
-    elif action == CALLBACK_RELOAD_ALL:
+    elif action == ENGINE_CALLBACK_RELOAD_ALL:
         Carla.gui.ReloadAllCallback.emit(pluginId)
-    elif action == CALLBACK_PATCHBAY_CLIENT_ADDED:
-        Carla.gui.PatchbayClientAddedCallback.emit(value1, cString(valueStr))
-    elif action == CALLBACK_PATCHBAY_CLIENT_REMOVED:
-        Carla.gui.PatchbayClientRemovedCallback.emit(value1, cString(valueStr))
-    elif action == CALLBACK_PATCHBAY_CLIENT_RENAMED:
-        Carla.gui.PatchbayClientRenamedCallback.emit(value1, cString(valueStr))
-    elif action == CALLBACK_PATCHBAY_PORT_ADDED:
-        Carla.gui.PatchbayPortAddedCallback.emit(value1, value2, int(value3), cString(valueStr))
-    elif action == CALLBACK_PATCHBAY_PORT_REMOVED:
-        Carla.gui.PatchbayPortRemovedCallback.emit(value1, value2, cString(valueStr))
-    elif action == CALLBACK_PATCHBAY_PORT_RENAMED:
-        Carla.gui.PatchbayPortRenamedCallback.emit(value1, value2, cString(valueStr))
-    elif action == CALLBACK_PATCHBAY_CONNECTION_ADDED:
+    elif action == ENGINE_CALLBACK_PATCHBAY_CLIENT_ADDED:
+        Carla.gui.PatchbayClientAddedCallback.emit(value1, charPtrToString(valueStr))
+    elif action == ENGINE_CALLBACK_PATCHBAY_CLIENT_REMOVED:
+        Carla.gui.PatchbayClientRemovedCallback.emit(value1, charPtrToString(valueStr))
+    elif action == ENGINE_CALLBACK_PATCHBAY_CLIENT_RENAMED:
+        Carla.gui.PatchbayClientRenamedCallback.emit(value1, charPtrToString(valueStr))
+    elif action == ENGINE_CALLBACK_PATCHBAY_PORT_ADDED:
+        Carla.gui.PatchbayPortAddedCallback.emit(value1, value2, int(value3), charPtrToString(valueStr))
+    elif action == ENGINE_CALLBACK_PATCHBAY_PORT_REMOVED:
+        Carla.gui.PatchbayPortRemovedCallback.emit(value1, value2, charPtrToString(valueStr))
+    elif action == ENGINE_CALLBACK_PATCHBAY_PORT_RENAMED:
+        Carla.gui.PatchbayPortRenamedCallback.emit(value1, value2, charPtrToString(valueStr))
+    elif action == ENGINE_CALLBACK_PATCHBAY_CONNECTION_ADDED:
         Carla.gui.PatchbayConnectionAddedCallback.emit(value1, value2, value3)
-    elif action == CALLBACK_PATCHBAY_CONNECTION_REMOVED:
+    elif action == ENGINE_CALLBACK_PATCHBAY_CONNECTION_REMOVED:
         Carla.gui.PatchbayConnectionRemovedCallback.emit(value1)
-    elif action == CALLBACK_PATCHBAY_ICON_CHANGED:
-        Carla.gui.PatchbayIconChangedCallback.emit(value1, cString(valueStr))
-    elif action == CALLBACK_BUFFER_SIZE_CHANGED:
+    #elif action == ENGINE_CALLBACK_PATCHBAY_ICON_CHANGED:
+        #Carla.gui.PatchbayIconChangedCallback.emit(value1, charPtrToString(valueStr))
+    elif action == ENGINE_CALLBACK_BUFFER_SIZE_CHANGED:
         Carla.gui.BufferSizeChangedCallback.emit(value1)
-    elif action == CALLBACK_SAMPLE_RATE_CHANGED:
+    elif action == ENGINE_CALLBACK_SAMPLE_RATE_CHANGED:
         Carla.gui.SampleRateChangedCallback.emit(value3)
-    elif action == CALLBACK_PROCESS_MODE_CHANGED:
+    elif action == ENGINE_CALLBACK_PROCESS_MODE_CHANGED:
         Carla.gui.ProcessModeChangedCallback.emit(value1)
-    elif action == CALLBACK_ENGINE_STARTED:
-        Carla.gui.EngineStartedCallback.emit(cString(valueStr))
-    elif action == CALLBACK_ENGINE_STOPPED:
+    elif action == ENGINE_CALLBACK_ENGINE_STARTED:
+        Carla.gui.EngineStartedCallback.emit(charPtrToString(valueStr))
+    elif action == ENGINE_CALLBACK_ENGINE_STOPPED:
         Carla.gui.EngineStoppedChangedCallback.emit()
-    elif action == CALLBACK_NSM_ANNOUNCE:
-        Carla.gui.NSM_AnnounceCallback.emit(cString(valueStr))
-    elif action == CALLBACK_NSM_OPEN:
-        Carla.gui.NSM_OpenCallback.emit(cString(valueStr))
-    elif action == CALLBACK_NSM_SAVE:
-        Carla.gui.NSM_SaveCallback.emit()
-    elif action == CALLBACK_ERROR:
-        Carla.gui.ErrorCallback.emit(cString(valueStr))
-    elif action == CALLBACK_QUIT:
+    #elif action == CALLBACK_NSM_ANNOUNCE:
+        #Carla.gui.NSM_AnnounceCallback.emit(charPtrToString(valueStr))
+    #elif action == CALLBACK_NSM_OPEN:
+        #Carla.gui.NSM_OpenCallback.emit(charPtrToString(valueStr))
+    #elif action == CALLBACK_NSM_SAVE:
+        #Carla.gui.NSM_SaveCallback.emit()
+    elif action == ENGINE_CALLBACK_ERROR:
+        Carla.gui.ErrorCallback.emit(charPtrToString(valueStr))
+    elif action == ENGINE_CALLBACK_QUIT:
         Carla.gui.QuitCallback.emit()
diff --git a/source/carla_patchbay.py b/source/carla_patchbay.py
index ff372f93d..ce58d8cb5 100644
--- a/source/carla_patchbay.py
+++ b/source/carla_patchbay.py
@@ -38,10 +38,10 @@ from carla_widgets import *
 # Try Import OpenGL
 
 try:
-    try:
-        from PyQt5.QtOpenGL import QGLWidget
-    except:
-        from PyQt4.QtOpenGL import QGLWidget
+    #try:
+        #from PyQt5.QtOpenGL import QGLWidget
+    #except:
+    from PyQt4.QtOpenGL import QGLWidget
     hasGL = True
 except:
     hasGL = False
diff --git a/source/carla_settings.py b/source/carla_settings.py
index c50cbd3c0..f83b8b3a1 100755
--- a/source/carla_settings.py
+++ b/source/carla_settings.py
@@ -84,11 +84,11 @@ else:
     CARLA_DEFAULT_AUDIO_DRIVER = "JACK"
 
 if LINUX:
-    CARLA_DEFAULT_PROCESS_MODE   = PROCESS_MODE_MULTIPLE_CLIENTS
-    CARLA_DEFAULT_TRANSPORT_MODE = TRANSPORT_MODE_JACK
+    CARLA_DEFAULT_PROCESS_MODE   = ENGINE_PROCESS_MODE_MULTIPLE_CLIENTS
+    CARLA_DEFAULT_TRANSPORT_MODE = ENGINE_TRANSPORT_MODE_JACK
 else:
-    CARLA_DEFAULT_PROCESS_MODE   = PROCESS_MODE_CONTINUOUS_RACK
-    CARLA_DEFAULT_TRANSPORT_MODE = TRANSPORT_MODE_INTERNAL
+    CARLA_DEFAULT_PROCESS_MODE   = ENGINE_PROCESS_MODE_CONTINUOUS_RACK
+    CARLA_DEFAULT_TRANSPORT_MODE = ENGINE_TRANSPORT_MODE_INTERNAL
 
 # ------------------------------------------------------------------------------------------------------------
 # ...
@@ -105,10 +105,6 @@ class DriverSettingsW(QDialog):
         self.ui = ui_carla_settings_driver.Ui_DriverSettingsW()
         self.ui.setupUi(self)
 
-        if driverName == "JACK":
-            print("This dialog is not compatible with JACK")
-            return
-
         # -------------------------------------------------------------
         # Internal stuff
 
@@ -218,7 +214,7 @@ class CarlaSettingsW(QDialog):
 
         if Carla.host is not None:
             for i in range(Carla.host.get_engine_driver_count()):
-                self.ui.cb_engine_audio_driver.addItem(cString(Carla.host.get_engine_driver_name(i)))
+                self.ui.cb_engine_audio_driver.addItem(Carla.host.get_engine_driver_name(i))
         else:
             self.ui.tb_engine_driver_config.setEnabled(False)
 
@@ -324,11 +320,11 @@ class CarlaSettingsW(QDialog):
             self.ui.cb_engine_audio_driver.setCurrentIndex(-1)
 
         if audioDriver == "JACK":
-            processModeIndex = settings.value(CARLA_KEY_ENGINE_PROCESS_MODE, PROCESS_MODE_MULTIPLE_CLIENTS, type=int)
+            processModeIndex = settings.value(CARLA_KEY_ENGINE_PROCESS_MODE, ENGINE_PROCESS_MODE_MULTIPLE_CLIENTS, type=int)
             self.ui.cb_engine_process_mode_jack.setCurrentIndex(processModeIndex)
             self.ui.sw_engine_process_mode.setCurrentIndex(0)
         else:
-            processModeIndex  = settings.value(CARLA_KEY_ENGINE_PROCESS_MODE, PROCESS_MODE_CONTINUOUS_RACK, type=int)
+            processModeIndex  = settings.value(CARLA_KEY_ENGINE_PROCESS_MODE, ENGINE_PROCESS_MODE_CONTINUOUS_RACK, type=int)
             processModeIndex -= self.PROCESS_MODE_NON_JACK_PADDING
             self.ui.cb_engine_process_mode_other.setCurrentIndex(processModeIndex)
             self.ui.sw_engine_process_mode.setCurrentIndex(1)
@@ -517,10 +513,10 @@ class CarlaSettingsW(QDialog):
             self.ui.ch_engine_prefer_plugin_bridges.setChecked(CARLA_DEFAULT_PREFER_PLUGIN_BRIDGES)
 
             if self.ui.cb_engine_audio_driver.currentText() == "JACK":
-                self.ui.cb_engine_process_mode_jack.setCurrentIndex(PROCESS_MODE_MULTIPLE_CLIENTS)
+                self.ui.cb_engine_process_mode_jack.setCurrentIndex(ENGINE_PROCESS_MODE_MULTIPLE_CLIENTS)
                 self.ui.sw_engine_process_mode.setCurrentIndex(0) # show all modes
             else:
-                self.ui.cb_engine_process_mode_other.setCurrentIndex(PROCESS_MODE_CONTINUOUS_RACK-self.PROCESS_MODE_NON_JACK_PADDING)
+                self.ui.cb_engine_process_mode_other.setCurrentIndex(ENGINE_PROCESS_MODE_CONTINUOUS_RACK-self.PROCESS_MODE_NON_JACK_PADDING)
                 self.ui.sw_engine_process_mode.setCurrentIndex(1) # hide single+multi client modes
 
         elif self.ui.lw_page.currentRow() == self.TAB_INDEX_PATHS:
diff --git a/source/carla_widgets.py b/source/carla_widgets.py
index e92dfec54..f18239658 100755
--- a/source/carla_widgets.py
+++ b/source/carla_widgets.py
@@ -1055,6 +1055,9 @@ class PluginEdit(QDialog):
 
     @pyqtSlot(bool)
     def slot_optionChanged(self, clicked):
+        if Carla.host is None:
+            return
+
         sender = self.sender()
 
         if sender == self.ui.ch_fixed_buffer:
@@ -1082,52 +1085,67 @@ class PluginEdit(QDialog):
 
     @pyqtSlot(int)
     def slot_dryWetChanged(self, value):
-        Carla.host.set_drywet(self.fPluginId, float(value)/1000)
+        if Carla.host is not None:
+            Carla.host.set_drywet(self.fPluginId, float(value)/1000)
 
     @pyqtSlot(int)
     def slot_volumeChanged(self, value):
-        Carla.host.set_volume(self.fPluginId, float(value)/1000)
+        if Carla.host is not None:
+            Carla.host.set_volume(self.fPluginId, float(value)/1000)
 
     @pyqtSlot(int)
     def slot_balanceLeftChanged(self, value):
-        Carla.host.set_balance_left(self.fPluginId, float(value)/1000)
+        if Carla.host is not None:
+            Carla.host.set_balance_left(self.fPluginId, float(value)/1000)
 
     @pyqtSlot(int)
     def slot_balanceRightChanged(self, value):
-        Carla.host.set_balance_right(self.fPluginId, float(value)/1000)
+        if Carla.host is not None:
+            Carla.host.set_balance_right(self.fPluginId, float(value)/1000)
 
     @pyqtSlot(int)
     def slot_panningChanged(self, value):
-        Carla.host.set_panning(self.fPluginId, float(value)/1000)
+        if Carla.host is not None:
+            Carla.host.set_panning(self.fPluginId, float(value)/1000)
 
     @pyqtSlot(int)
     def slot_ctrlChannelChanged(self, value):
         self.fControlChannel = value-1
-        Carla.host.set_ctrl_channel(self.fPluginId, self.fControlChannel)
+
+        if Carla.host is not None:
+            Carla.host.set_ctrl_channel(self.fPluginId, self.fControlChannel)
+
         self.ui.keyboard.allNotesOff()
         self._updateCtrlMidiProgram()
 
     @pyqtSlot(int, float)
     def slot_parameterValueChanged(self, parameterId, value):
-        Carla.host.set_parameter_value(self.fPluginId, parameterId, value)
+        if Carla.host is not None:
+            Carla.host.set_parameter_value(self.fPluginId, parameterId, value)
 
     @pyqtSlot(int, int)
     def slot_parameterMidiControlChanged(self, parameterId, control):
-        Carla.host.set_parameter_midi_cc(self.fPluginId, parameterId, control)
+        if Carla.host is not None:
+            Carla.host.set_parameter_midi_cc(self.fPluginId, parameterId, control)
 
     @pyqtSlot(int, int)
     def slot_parameterMidiChannelChanged(self, parameterId, channel):
-        Carla.host.set_parameter_midi_channel(self.fPluginId, parameterId, channel-1)
+        if Carla.host is not None:
+            Carla.host.set_parameter_midi_channel(self.fPluginId, parameterId, channel-1)
 
     @pyqtSlot(int)
     def slot_programIndexChanged(self, index):
         self.fCurrentProgram = index
-        Carla.host.set_program(self.fPluginId, index)
+
+        if Carla.host is not None:
+            Carla.host.set_program(self.fPluginId, index)
 
     @pyqtSlot(int)
     def slot_midiProgramIndexChanged(self, index):
         self.fCurrentMidiProgram = index
-        Carla.host.set_midi_program(self.fPluginId, index)
+
+        if Carla.host is not None:
+            Carla.host.set_midi_program(self.fPluginId, index)
 
     @pyqtSlot(int)
     def slot_noteOn(self, note):
diff --git a/source/patchcanvas.py b/source/patchcanvas.py
index 395c5dca3..3e6777221 100644
--- a/source/patchcanvas.py
+++ b/source/patchcanvas.py
@@ -17,24 +17,24 @@
 # For a full copy of the GNU General Public License see the GPL.txt file
 
 # Imports (Global)
-try:
-    from PyQt5.QtCore import pyqtSignal, pyqtSlot, qDebug, qCritical, qFatal, qWarning, Qt, QObject
-    from PyQt5.QtCore import QAbstractAnimation, QLineF, QPointF, QRectF, QSizeF, QSettings, QTimer
-    from PyQt5.QtGui import QColor, QLinearGradient, QPen, QPolygonF, QPainter, QPainterPath
-    from PyQt5.QtGui import QCursor, QFont, QFontMetrics
-    from PyQt5.QtSvg import QGraphicsSvgItem, QSvgRenderer
-    from PyQt5.QtWidgets import QGraphicsScene, QGraphicsItem, QGraphicsLineItem, QGraphicsPathItem
-    from PyQt5.QtWidgets import QGraphicsColorizeEffect, QGraphicsDropShadowEffect
-    from PyQt5.QtWidgets import QInputDialog, QLineEdit, QMenu
-except:
-    from PyQt4.QtCore import pyqtSignal, pyqtSlot, qDebug, qCritical, qFatal, qWarning, Qt, QObject
-    from PyQt4.QtCore import QAbstractAnimation, QLineF, QPointF, QRectF, QSizeF, QSettings, QTimer
-    from PyQt4.QtGui import QColor, QLinearGradient, QPen, QPolygonF, QPainter, QPainterPath
-    from PyQt4.QtGui import QCursor, QFont, QFontMetrics
-    from PyQt4.QtGui import QGraphicsScene, QGraphicsItem, QGraphicsLineItem, QGraphicsPathItem
-    from PyQt4.QtGui import QGraphicsColorizeEffect, QGraphicsDropShadowEffect
-    from PyQt4.QtGui import QInputDialog, QLineEdit, QMenu
-    from PyQt4.QtSvg import QGraphicsSvgItem, QSvgRenderer
+#try:
+    #from PyQt5.QtCore import pyqtSignal, pyqtSlot, qDebug, qCritical, qFatal, qWarning, Qt, QObject
+    #from PyQt5.QtCore import QAbstractAnimation, QLineF, QPointF, QRectF, QSizeF, QSettings, QTimer
+    #from PyQt5.QtGui import QColor, QLinearGradient, QPen, QPolygonF, QPainter, QPainterPath
+    #from PyQt5.QtGui import QCursor, QFont, QFontMetrics
+    #from PyQt5.QtSvg import QGraphicsSvgItem, QSvgRenderer
+    #from PyQt5.QtWidgets import QGraphicsScene, QGraphicsItem, QGraphicsLineItem, QGraphicsPathItem
+    #from PyQt5.QtWidgets import QGraphicsColorizeEffect, QGraphicsDropShadowEffect
+    #from PyQt5.QtWidgets import QInputDialog, QLineEdit, QMenu
+#except:
+from PyQt4.QtCore import pyqtSignal, pyqtSlot, qDebug, qCritical, qFatal, qWarning, Qt, QObject
+from PyQt4.QtCore import QAbstractAnimation, QLineF, QPointF, QRectF, QSizeF, QSettings, QTimer
+from PyQt4.QtGui import QColor, QLinearGradient, QPen, QPolygonF, QPainter, QPainterPath
+from PyQt4.QtGui import QCursor, QFont, QFontMetrics
+from PyQt4.QtGui import QGraphicsScene, QGraphicsItem, QGraphicsLineItem, QGraphicsPathItem
+from PyQt4.QtGui import QGraphicsColorizeEffect, QGraphicsDropShadowEffect
+from PyQt4.QtGui import QInputDialog, QLineEdit, QMenu
+from PyQt4.QtSvg import QGraphicsSvgItem, QSvgRenderer
 
 # Imports (Theme)
 from patchcanvas_theme import *
diff --git a/source/patchcanvas_theme.py b/source/patchcanvas_theme.py
index 629697de9..ec2bce3b8 100644
--- a/source/patchcanvas_theme.py
+++ b/source/patchcanvas_theme.py
@@ -19,12 +19,12 @@
 # ------------------------------------------------------------------------------------------------------------
 # Imports (Global)
 
-try:
-    from PyQt5.QtCore import Qt
-    from PyQt5.QtGui import QColor, QFont, QPen, QPixmap
-except:
-    from PyQt4.QtCore import Qt
-    from PyQt4.QtGui import QColor, QFont, QPen, QPixmap
+#try:
+    #from PyQt5.QtCore import Qt
+    #from PyQt5.QtGui import QColor, QFont, QPen, QPixmap
+#except:
+from PyQt4.QtCore import Qt
+from PyQt4.QtGui import QColor, QFont, QPen, QPixmap
 
 # ------------------------------------------------------------------------------------------------------------
 # patchcanvas-theme.cpp
diff --git a/source/widgets/canvaspreviewframe.py b/source/widgets/canvaspreviewframe.py
index 939b94078..e4f804d06 100644
--- a/source/widgets/canvaspreviewframe.py
+++ b/source/widgets/canvaspreviewframe.py
@@ -20,13 +20,13 @@
 # Imports (Global)
 
 # TODO - SIGNAL, SLOT
-try:
-  from PyQt5.QtCore import Qt, QRectF, QTimer
-  from PyQt5.QtGui import QBrush, QColor, QCursor, QPainter, QPen
-  from PyQt5.QtWidgets import QFrame
-except:
-  from PyQt4.QtCore import Qt, QRectF, QTimer
-  from PyQt4.QtGui import QBrush, QColor, QCursor, QFrame, QPainter, QPen
+#try:
+  #from PyQt5.QtCore import Qt, QRectF, QTimer
+  #from PyQt5.QtGui import QBrush, QColor, QCursor, QPainter, QPen
+  #from PyQt5.QtWidgets import QFrame
+#except:
+from PyQt4.QtCore import Qt, QRectF, QTimer
+from PyQt4.QtGui import QBrush, QColor, QCursor, QFrame, QPainter, QPen
 
 # ------------------------------------------------------------------------------------------------------------
 # Static Variables
diff --git a/source/widgets/digitalpeakmeter.py b/source/widgets/digitalpeakmeter.py
index 369e464e0..03801fb7b 100644
--- a/source/widgets/digitalpeakmeter.py
+++ b/source/widgets/digitalpeakmeter.py
@@ -19,13 +19,13 @@
 # ------------------------------------------------------------------------------------------------------------
 # Imports (Global)
 
-try:
-    from PyQt5.QtCore import qCritical, Qt, QTimer, QSize
-    from PyQt5.QtGui import QColor, QLinearGradient, QPainter
-    from PyQt5.QtWidgets import QWidget
-except:
-    from PyQt4.QtCore import qCritical, Qt, QTimer, QSize
-    from PyQt4.QtGui import QColor, QLinearGradient, QPainter, QWidget
+#try:
+    #from PyQt5.QtCore import qCritical, Qt, QTimer, QSize
+    #from PyQt5.QtGui import QColor, QLinearGradient, QPainter
+    #from PyQt5.QtWidgets import QWidget
+#except:
+from PyQt4.QtCore import qCritical, Qt, QTimer, QSize
+from PyQt4.QtGui import QColor, QLinearGradient, QPainter, QWidget
 
 # ------------------------------------------------------------------------------------------------------------
 # Widget Class
diff --git a/source/widgets/ledbutton.py b/source/widgets/ledbutton.py
index c1732dfa2..07855686d 100644
--- a/source/widgets/ledbutton.py
+++ b/source/widgets/ledbutton.py
@@ -19,13 +19,13 @@
 # ------------------------------------------------------------------------------------------------------------
 # Imports (Global)
 
-try:
-    from PyQt5.QtCore import qCritical, QRectF
-    from PyQt5.QtGui import QPainter, QPixmap
-    from PyQt5.QtWidgets import QPushButton
-except:
-    from PyQt4.QtCore import qCritical, QRectF
-    from PyQt4.QtGui import QPainter, QPixmap, QPushButton
+#try:
+    #from PyQt5.QtCore import qCritical, QRectF
+    #from PyQt5.QtGui import QPainter, QPixmap
+    #from PyQt5.QtWidgets import QPushButton
+#except:
+from PyQt4.QtCore import qCritical, QRectF
+from PyQt4.QtGui import QPainter, QPixmap, QPushButton
 
 # ------------------------------------------------------------------------------------------------------------
 # Widget Class
diff --git a/source/widgets/paramspinbox.py b/source/widgets/paramspinbox.py
index 527bfa959..4138263f2 100644
--- a/source/widgets/paramspinbox.py
+++ b/source/widgets/paramspinbox.py
@@ -19,13 +19,13 @@
 # ------------------------------------------------------------------------------------------------------------
 # Imports (Global)
 
-try:
-    from PyQt5.QtCore import pyqtSignal, pyqtSlot, Qt, QTimer
-    from PyQt5.QtGui import QCursor
-    from PyQt5.QtWidgets import QAbstractSpinBox, QApplication, QComboBox, QDialog, QMenu, QProgressBar
-except:
-    from PyQt4.QtCore import pyqtSignal, pyqtSlot, Qt, QTimer
-    from PyQt4.QtGui import QAbstractSpinBox, QApplication, QComboBox, QCursor, QDialog, QMenu, QProgressBar
+#try:
+    #from PyQt5.QtCore import pyqtSignal, pyqtSlot, Qt, QTimer
+    #from PyQt5.QtGui import QCursor
+    #from PyQt5.QtWidgets import QAbstractSpinBox, QApplication, QComboBox, QDialog, QMenu, QProgressBar
+#except:
+from PyQt4.QtCore import pyqtSignal, pyqtSlot, Qt, QTimer
+from PyQt4.QtGui import QAbstractSpinBox, QApplication, QComboBox, QCursor, QDialog, QMenu, QProgressBar
 
 from math import isnan
 
diff --git a/source/widgets/pixmapbutton.py b/source/widgets/pixmapbutton.py
index 38d4243ba..916c9b454 100644
--- a/source/widgets/pixmapbutton.py
+++ b/source/widgets/pixmapbutton.py
@@ -19,13 +19,13 @@
 # ------------------------------------------------------------------------------------------------------------
 # Imports (Global)
 
-try:
-    from PyQt5.QtCore import QRectF
-    from PyQt5.QtGui import QPainter, QPixmap
-    from PyQt5.QtWidgets import QPushButton
-except:
-    from PyQt4.QtCore import QRectF
-    from PyQt4.QtGui import QPainter, QPixmap, QPushButton
+#try:
+    #from PyQt5.QtCore import QRectF
+    #from PyQt5.QtGui import QPainter, QPixmap
+    #from PyQt5.QtWidgets import QPushButton
+#except:
+from PyQt4.QtCore import QRectF
+from PyQt4.QtGui import QPainter, QPixmap, QPushButton
 
 # ------------------------------------------------------------------------------------------------------------
 # Widget Class
diff --git a/source/widgets/pixmapdial.py b/source/widgets/pixmapdial.py
index bb3c8efaf..2637cf742 100644
--- a/source/widgets/pixmapdial.py
+++ b/source/widgets/pixmapdial.py
@@ -21,15 +21,15 @@
 
 from math import floor
 
-try:
-    from PyQt5.QtCore import Qt, QPointF, QRectF, QTimer, QSize
-    from PyQt5.QtGui import QColor, QConicalGradient, QFont, QFontMetrics
-    from PyQt5.QtGui import QLinearGradient, QPainter, QPainterPath, QPen, QPixmap
-    from PyQt5.QtWidgets import QDial
-except:
-    from PyQt4.QtCore import Qt, QPointF, QRectF, QTimer, QSize
-    from PyQt4.QtGui import QColor, QConicalGradient, QFont, QFontMetrics
-    from PyQt4.QtGui import QDial, QLinearGradient, QPainter, QPainterPath, QPen, QPixmap
+#try:
+    #from PyQt5.QtCore import Qt, QPointF, QRectF, QTimer, QSize
+    #from PyQt5.QtGui import QColor, QConicalGradient, QFont, QFontMetrics
+    #from PyQt5.QtGui import QLinearGradient, QPainter, QPainterPath, QPen, QPixmap
+    #from PyQt5.QtWidgets import QDial
+#except:
+from PyQt4.QtCore import Qt, QPointF, QRectF, QTimer, QSize
+from PyQt4.QtGui import QColor, QConicalGradient, QFont, QFontMetrics
+from PyQt4.QtGui import QDial, QLinearGradient, QPainter, QPainterPath, QPen, QPixmap
 
 # ------------------------------------------------------------------------------------------------------------
 # Widget Class
diff --git a/source/widgets/pixmapkeyboard.py b/source/widgets/pixmapkeyboard.py
index d93a6ae66..d857fb865 100644
--- a/source/widgets/pixmapkeyboard.py
+++ b/source/widgets/pixmapkeyboard.py
@@ -19,13 +19,13 @@
 # ------------------------------------------------------------------------------------------------------------
 # Imports (Global)
 
-try:
-    from PyQt5.QtCore import pyqtSignal, qCritical, Qt, QPointF, QRectF, QSize
-    from PyQt5.QtGui import QFont, QPainter, QPixmap
-    from PyQt5.QtWidgets import QWidget
-except:
-    from PyQt4.QtCore import pyqtSignal, qCritical, Qt, QPointF, QRectF, QSize
-    from PyQt4.QtGui import QFont, QPainter, QPixmap, QWidget
+#try:
+    #from PyQt5.QtCore import pyqtSignal, qCritical, Qt, QPointF, QRectF, QSize
+    #from PyQt5.QtGui import QFont, QPainter, QPixmap
+    #from PyQt5.QtWidgets import QWidget
+#except:
+from PyQt4.QtCore import pyqtSignal, qCritical, Qt, QPointF, QRectF, QSize
+from PyQt4.QtGui import QFont, QPainter, QPixmap, QWidget
 
 # ------------------------------------------------------------------------------------------------------------