diff --git a/README.md b/README.md
index 26efdfe84..0cfcea5ce 100644
--- a/README.md
+++ b/README.md
@@ -30,7 +30,7 @@ $ python3 -m pip install --user ".[gui,crypto]"
 
 If you want to use the Qt interface, install the Qt dependencies:
 ```
-$ sudo apt-get install python3-pyqt5
+$ sudo apt-get install python3-pyqt6
 ```
 
 For elliptic curve operations,
diff --git a/contrib/requirements/requirements.txt b/contrib/requirements/requirements.txt
index 484b2c592..2c85276bf 100644
--- a/contrib/requirements/requirements.txt
+++ b/contrib/requirements/requirements.txt
@@ -1,6 +1,6 @@
 qrcode
 protobuf>=3.20,<4
-qdarkstyle>=2.7
+qdarkstyle>=3.2
 aiorpcx>=0.22.0,<0.24
 aiohttp>=3.3.0,<4.0.0
 aiohttp_socks>=0.8.4
diff --git a/electrum/gui/common_qt/__init__.py b/electrum/gui/common_qt/__init__.py
index dec8c4193..97c1f5bae 100644
--- a/electrum/gui/common_qt/__init__.py
+++ b/electrum/gui/common_qt/__init__.py
@@ -2,15 +2,3 @@
 # Distributed under the MIT software license, see the accompanying
 # file LICENCE or http://www.opensource.org/licenses/mit-license.php
 
-import sys
-
-
-# FIXME: remove when both desktop and mobile are Qt6
-def get_qt_major_version() -> int:
-    _GUI_QT_VERSION = getattr(sys, '_GUI_QT_VERSION', None)
-    if _GUI_QT_VERSION is None:
-        # used by pyinstaller when building (analysis phase)
-        _GUI_QT_VERSION = 6
-    if _GUI_QT_VERSION in (5, 6):
-        return _GUI_QT_VERSION
-    raise Exception(f"unexpected {_GUI_QT_VERSION=}")
diff --git a/electrum/gui/common_qt/plugins.py b/electrum/gui/common_qt/plugins.py
index 9edaa9b19..3d87322bb 100644
--- a/electrum/gui/common_qt/plugins.py
+++ b/electrum/gui/common_qt/plugins.py
@@ -1,13 +1,6 @@
 import sys
 
-from . import get_qt_major_version
-
-if (qt_ver := get_qt_major_version()) == 5:
-    from PyQt5.QtCore import pyqtSignal, pyqtProperty, QObject
-elif qt_ver == 6:
-    from PyQt6.QtCore import pyqtSignal, pyqtProperty, QObject
-else:
-    raise Exception(f"unexpected {qt_ver=}")
+from PyQt6.QtCore import pyqtSignal, pyqtProperty, QObject
 
 from electrum.logging import get_logger
 
diff --git a/electrum/gui/qml/__init__.py b/electrum/gui/qml/__init__.py
index 7e28f61f5..ac04f4eb5 100644
--- a/electrum/gui/qml/__init__.py
+++ b/electrum/gui/qml/__init__.py
@@ -22,7 +22,6 @@ except Exception as e:
 
 from PyQt6.QtCore import (Qt, QCoreApplication, QLocale, QTranslator, QTimer, QT_VERSION_STR, PYQT_VERSION_STR)
 from PyQt6.QtGui import QGuiApplication
-sys._GUI_QT_VERSION = 6  # used by gui/common_qt
 
 from electrum.i18n import _
 from electrum.plugin import run_hook
diff --git a/electrum/gui/qt/__init__.py b/electrum/gui/qt/__init__.py
index 7f66c9239..3ff6f9b3e 100644
--- a/electrum/gui/qt/__init__.py
+++ b/electrum/gui/qt/__init__.py
@@ -42,7 +42,6 @@ from PyQt6.QtGui import QGuiApplication
 from PyQt6.QtWidgets import QApplication, QSystemTrayIcon, QWidget, QMenu, QMessageBox, QDialog
 from PyQt6.QtCore import QObject, pyqtSignal, QTimer, Qt
 import PyQt6.QtCore as QtCore
-sys._GUI_QT_VERSION = 6  # used by gui/common_qt
 
 try:
     # Preload QtMultimedia at app start, if available.
@@ -176,7 +175,7 @@ class ElectrumGui(BaseElectrumGui, Logger):
         if use_dark_theme:
             try:
                 import qdarkstyle
-                self.app.setStyleSheet(qdarkstyle.load_stylesheet_pyqt5())
+                self.app.setStyleSheet(qdarkstyle.load_stylesheet_pyqt6())
             except BaseException as e:
                 use_dark_theme = False
                 self.logger.warning(f'Error setting dark theme: {repr(e)}')
diff --git a/electrum/gui/qt/qrreader/__init__.py b/electrum/gui/qt/qrreader/__init__.py
index 4febc7d5b..38c54e214 100644
--- a/electrum/gui/qt/qrreader/__init__.py
+++ b/electrum/gui/qt/qrreader/__init__.py
@@ -12,7 +12,7 @@
 # - zbar fails to access the camera on macOS
 # - qtmultimedia seems to support more cameras on Windows than zbar
 # - qtmultimedia is often not packaged with PyQt
-#   in particular, on debian, you need both "python3-pyqt5" and "python3-pyqt5.qtmultimedia"
+#   in particular, on debian, you need both "python3-pyqt6" and "python3-pyqt6.qtmultimedia"
 # - older versions of qtmultimedia don't seem to work reliably
 #
 # Considering the above, we use QtMultimedia for Windows and macOS, as there
diff --git a/electrum/plugins/trustedcoin/common_qt.py b/electrum/plugins/trustedcoin/common_qt.py
index 85e082aca..5b4ef65c5 100644
--- a/electrum/plugins/trustedcoin/common_qt.py
+++ b/electrum/plugins/trustedcoin/common_qt.py
@@ -4,14 +4,7 @@ import base64
 import sys
 from typing import TYPE_CHECKING
 
-from electrum.gui.common_qt import get_qt_major_version
-
-if (qt_ver := get_qt_major_version()) == 5:
-    from PyQt5.QtCore import pyqtSignal, pyqtProperty, pyqtSlot
-elif qt_ver == 6:
-    from PyQt6.QtCore import pyqtSignal, pyqtProperty, pyqtSlot
-else:
-    raise Exception(f"unexpected {qt_ver=}")
+from PyQt6.QtCore import pyqtSignal, pyqtProperty, pyqtSlot
 
 from electrum.i18n import _
 from electrum.bip32 import BIP32Node
diff --git a/setup.py b/setup.py
index 733a8cf60..ddf604286 100755
--- a/setup.py
+++ b/setup.py
@@ -42,7 +42,7 @@ if platform.system() in ['Linux', 'FreeBSD', 'DragonFly']:
 
 extras_require = {
     'hardware': requirements_hw,
-    'gui': ['pyqt5'],
+    'gui': ['pyqt6'],
     'crypto': ['cryptography>=2.6'],
     'tests': ['pycryptodomex>=3.7', 'cryptography>=2.6', 'pyaes>=0.1a1'],
     'qml_gui': ['pyqt6', 'Pillow>=8.4.0']