diff --git a/electrum/gui/common_qt/plugins.py b/electrum/gui/common_qt/plugins.py
index 3403be027..0934477b4 100644
--- a/electrum/gui/common_qt/plugins.py
+++ b/electrum/gui/common_qt/plugins.py
@@ -1,4 +1,9 @@
-from PyQt6.QtCore import pyqtSignal, pyqtProperty, QObject  # TODO: common code, Qt5/Qt6 mismatch!
+import sys
+
+if getattr(sys, '_GUI_QT_VERSION') == 5:  # FIXME: remove when both desktop and mobile are Qt6
+    from PyQt5.QtCore import pyqtSignal, pyqtProperty, QObject
+else:
+    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 53e87c2e5..35926cb70 100644
--- a/electrum/gui/qml/__init__.py
+++ b/electrum/gui/qml/__init__.py
@@ -16,6 +16,7 @@ except Exception:
 
 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 025eca2e8..94c75fc8c 100644
--- a/electrum/gui/qt/__init__.py
+++ b/electrum/gui/qt/__init__.py
@@ -42,6 +42,7 @@ from PyQt5.QtGui import QGuiApplication
 from PyQt5.QtWidgets import QApplication, QSystemTrayIcon, QWidget, QMenu, QMessageBox
 from PyQt5.QtCore import QObject, pyqtSignal, QTimer, Qt
 import PyQt5.QtCore as QtCore
+sys._GUI_QT_VERSION = 5  # used by gui/common_qt
 
 try:
     # Preload QtMultimedia at app start, if available.
diff --git a/electrum/plugins/trustedcoin/common_qt.py b/electrum/plugins/trustedcoin/common_qt.py
index c960d5240..31b9954e7 100644
--- a/electrum/plugins/trustedcoin/common_qt.py
+++ b/electrum/plugins/trustedcoin/common_qt.py
@@ -1,9 +1,13 @@
 import threading
 import socket
 import base64
+import sys
 from typing import TYPE_CHECKING
 
-from PyQt6.QtCore import pyqtSignal, pyqtProperty, pyqtSlot  # TODO: common code, Qt5/Qt6 mismatch!
+if getattr(sys, '_GUI_QT_VERSION') == 5:  # FIXME: remove when both desktop and mobile are Qt6
+    from PyQt5.QtCore import pyqtSignal, pyqtProperty, pyqtSlot
+else:
+    from PyQt6.QtCore import pyqtSignal, pyqtProperty, pyqtSlot
 
 from electrum.i18n import _
 from electrum.bip32 import BIP32Node