diff --git a/examples/ExampleApp.py b/examples/ExampleApp.py
index 1175f264..458daf76 100644
--- a/examples/ExampleApp.py
+++ b/examples/ExampleApp.py
@@ -189,7 +189,7 @@ class PythonHighlighter(QSyntaxHighlighter):
     @property
     def styles(self):
         app = QtGui.QApplication.instance()
-        return DARK_STYLES if app.dark_mode else LIGHT_STYLES
+        return DARK_STYLES if app.property('darkMode') else LIGHT_STYLES
 
     def highlightBlock(self, text):
         """Apply syntax highlighting to the given block of text.
@@ -310,7 +310,7 @@ class ExampleLoader(QtGui.QMainWindow):
         self.ui.codeView.setCurrentCharFormat(f)
         # finally, override application automatic detection
         app = QtGui.QApplication.instance()
-        app.dark_mode = True
+        app.setProperty('darkMode', True)
 
     def updateTheme(self):
         self.hl = PythonHighlighter(self.ui.codeView.document())
diff --git a/examples/syntax.py b/examples/syntax.py
index 1079c128..2c547867 100644
--- a/examples/syntax.py
+++ b/examples/syntax.py
@@ -186,7 +186,7 @@ class PythonHighlighter(QSyntaxHighlighter):
     @property
     def styles(self):
         app = QtGui.QApplication.instance()
-        return DARK_STYLES if app.dark_mode else LIGHT_STYLES
+        return DARK_STYLES if app.property('darkMode') else LIGHT_STYLES
 
     def highlightBlock(self, text):
         """Apply syntax highlighting to the given block of text.
diff --git a/pyqtgraph/Qt.py b/pyqtgraph/Qt.py
index 91c4d1b0..22971dba 100644
--- a/pyqtgraph/Qt.py
+++ b/pyqtgraph/Qt.py
@@ -468,19 +468,12 @@ class App(QtGui.QApplication):
 
     def __init__(self, *args, **kwargs):
         super(App, self).__init__(*args, **kwargs)
-        if QT_LIB in ['PyQt5', 'PySide2', 'PySide6']:
-            # qt4 does not have paletteChanged signal!
-            self.paletteChanged.connect(self.onPaletteChange)
+        self.paletteChanged.connect(self.onPaletteChange)
         self.onPaletteChange(self.palette())
 
     def onPaletteChange(self, palette):
-        if QT_LIB in ['PyQt4', 'PySide']:
-            # Qt4 this is a QString
-            color = str(palette.base().color().name())
-        else:
-            # Qt5 has this as a str
-            color = palette.base().color().name()
-        self.dark_mode = color.lower() != "#ffffff"
+        color = palette.base().color().name()
+        self.setProperty('darkMode', color.lower() != "#ffffff")
 
 QAPP = None
 def mkQApp(name=None):