diff --git a/src/calibre/gui2/custom_column_widgets.py b/src/calibre/gui2/custom_column_widgets.py
index 2ac6f0b69d..0dae360b0d 100644
--- a/src/calibre/gui2/custom_column_widgets.py
+++ b/src/calibre/gui2/custom_column_widgets.py
@@ -557,7 +557,7 @@ class Text(Base):
 
     def edit(self):
         ctrl_or_shift_pressed = (QApplication.keyboardModifiers() &
-                (Qt.KeyboardModifier.ControlModifier + Qt.KeyboardModifier.ShiftModifier))
+                (Qt.KeyboardModifier.ControlModifier | Qt.KeyboardModifier.ShiftModifier))
         if (self.getter() != self.initial_val and (self.getter() or self.initial_val)):
             d = _save_dialog(self.parent, _('Values changed'),
                     _('You have changed the values. In order to use this '
diff --git a/src/calibre/gui2/dialogs/choose_library.ui b/src/calibre/gui2/dialogs/choose_library.ui
index 9de32e61d2..b2e2f47ad5 100644
--- a/src/calibre/gui2/dialogs/choose_library.ui
+++ b/src/calibre/gui2/dialogs/choose_library.ui
@@ -140,7 +140,7 @@ user categories, and other information from the old to the new library</string>
    <item row="2" column="1" colspan="2">
     <widget class="HistoryLineEdit" name="location">
      <property name="sizeAdjustPolicy">
-      <enum>QComboBox::AdjustToMinimumContentsLength</enum>
+      <enum>QComboBox::AdjustToMinimumContentsLengthWithIcon</enum>
      </property>
      <property name="minimumContentsLength">
       <number>40</number>
diff --git a/src/calibre/gui2/dialogs/template_dialog.py b/src/calibre/gui2/dialogs/template_dialog.py
index f650dacec8..f0414ebb0b 100644
--- a/src/calibre/gui2/dialogs/template_dialog.py
+++ b/src/calibre/gui2/dialogs/template_dialog.py
@@ -506,7 +506,7 @@ class TemplateDialog(QDialog, Ui_TemplateDialog):
 
     def set_word_wrap(self, to_what):
         gprefs['gpm_template_editor_word_wrap_mode'] = to_what
-        self.textbox.setWordWrapMode(QTextOption.WordWrap if to_what else QTextOption.NoWrap)
+        self.textbox.setWordWrapMode(QTextOption.WrapMode.WordWrap if to_what else QTextOption.WrapMode.NoWrap)
 
     def load_last_template_text(self):
         from calibre.customize.ui import find_plugin
@@ -561,7 +561,7 @@ class TemplateDialog(QDialog, Ui_TemplateDialog):
 
     def set_up_font_boxes(self):
         font = self.get_current_font()
-        self.font_box.setWritingSystem(QFontDatabase.Latin)
+        self.font_box.setWritingSystem(QFontDatabase.WritingSystem.Latin)
         self.font_box.setCurrentFont(font)
         self.font_box.setEditable(False)
         gprefs['gpm_template_editor_font'] = str(font.family())
diff --git a/src/calibre/gui2/library/delegates.py b/src/calibre/gui2/library/delegates.py
index c2a0cfe039..bfa5547c3b 100644
--- a/src/calibre/gui2/library/delegates.py
+++ b/src/calibre/gui2/library/delegates.py
@@ -157,7 +157,7 @@ ClearingDoubleSpinBox = make_clearing_spinbox(QDoubleSpinBox)
 
 
 def check_key_modifier(which_modifier):
-    v = int(QApplication.keyboardModifiers() & (Qt.KeyboardModifier.ControlModifier + Qt.KeyboardModifier.ShiftModifier))
+    v = QApplication.keyboardModifiers() & (Qt.KeyboardModifier.ControlModifier | Qt.KeyboardModifier.ShiftModifier)
     return v == which_modifier
 
 
@@ -240,7 +240,7 @@ class DateDelegate(QStyledItemDelegate, UpdateEditorGeometry):  # {{{
     def setEditorData(self, editor, index):
         if check_key_modifier(Qt.KeyboardModifier.ControlModifier):
             val = UNDEFINED_QDATETIME
-        elif check_key_modifier(Qt.KeyboardModifier.ShiftModifier + Qt.KeyboardModifier.ControlModifier):
+        elif check_key_modifier(Qt.KeyboardModifier.ShiftModifier | Qt.KeyboardModifier.ControlModifier):
             val = now()
         else:
             val = index.data(Qt.ItemDataRole.EditRole)
@@ -273,7 +273,7 @@ class PubDateDelegate(QStyledItemDelegate, UpdateEditorGeometry):  # {{{
         val = index.data(Qt.ItemDataRole.EditRole)
         if check_key_modifier(Qt.KeyboardModifier.ControlModifier):
             val = UNDEFINED_QDATETIME
-        elif check_key_modifier(Qt.KeyboardModifier.ShiftModifier + Qt.KeyboardModifier.ControlModifier):
+        elif check_key_modifier(Qt.KeyboardModifier.ShiftModifier | Qt.KeyboardModifier.ControlModifier):
             val = now()
         elif is_date_undefined(val):
             val = QDate.currentDate()
@@ -446,7 +446,7 @@ class CcDateDelegate(QStyledItemDelegate, UpdateEditorGeometry):  # {{{
     def setEditorData(self, editor, index):
         if check_key_modifier(Qt.KeyboardModifier.ControlModifier):
             val = UNDEFINED_QDATETIME
-        elif check_key_modifier(Qt.KeyboardModifier.ShiftModifier + Qt.KeyboardModifier.ControlModifier):
+        elif check_key_modifier(Qt.KeyboardModifier.ShiftModifier | Qt.KeyboardModifier.ControlModifier):
             val = now()
         else:
             val = index.data(Qt.ItemDataRole.EditRole)
diff --git a/src/calibre/gui2/metadata/basic_widgets.py b/src/calibre/gui2/metadata/basic_widgets.py
index b742d97dd1..dc4f94b3e9 100644
--- a/src/calibre/gui2/metadata/basic_widgets.py
+++ b/src/calibre/gui2/metadata/basic_widgets.py
@@ -1434,7 +1434,7 @@ class TagsEdit(EditWithComplete, ToMetadataMixin):  # {{{
 
     def edit(self, db, id_):
         ctrl_or_shift_pressed = (QApplication.keyboardModifiers() &
-                (Qt.KeyboardModifier.ControlModifier + Qt.KeyboardModifier.ShiftModifier))
+                (Qt.KeyboardModifier.ControlModifier | Qt.KeyboardModifier.ShiftModifier))
         if self.changed:
             d = save_dialog(self, _('Tags changed'),
                     _('You have changed the tags. In order to use the tags'
diff --git a/src/calibre/gui2/preferences/tweaks.py b/src/calibre/gui2/preferences/tweaks.py
index 8e5bf3e57d..db7f043858 100644
--- a/src/calibre/gui2/preferences/tweaks.py
+++ b/src/calibre/gui2/preferences/tweaks.py
@@ -393,7 +393,7 @@ class ConfigWidget(ConfigWidgetBase):
 
         self.search = sb = SearchBox2(self)
         sb.sizePolicy().setHorizontalStretch(10)
-        sb.setSizeAdjustPolicy(QComboBox.SizeAdjustPolicy.AdjustToMinimumContentsLength)
+        sb.setSizeAdjustPolicy(QComboBox.SizeAdjustPolicy.AdjustToMinimumContentsLengthWithIcon)
         sb.setMinimumContentsLength(10)
         g.setColumnStretch(0, 100)
         g.addWidget(self.search, 0, 0, 1, 1)
diff --git a/src/calibre/gui2/qt_file_dialogs.py b/src/calibre/gui2/qt_file_dialogs.py
index 75a7fc52b1..296d419cf3 100644
--- a/src/calibre/gui2/qt_file_dialogs.py
+++ b/src/calibre/gui2/qt_file_dialogs.py
@@ -96,7 +96,7 @@ class FileDialog(QObject):
         self.selected_files = []
         use_native_dialog = 'CALIBRE_NO_NATIVE_FILEDIALOGS' not in os.environ
         with sanitize_env_vars():
-            opts = QFileDialog.Option()
+            opts = QFileDialog.Option(0)
             if not use_native_dialog:
                 opts |= QFileDialog.Option.DontUseNativeDialog
             if has_long_filter:
diff --git a/src/calibre/gui2/widgets.py b/src/calibre/gui2/widgets.py
index e03731d310..e9255c7f16 100644
--- a/src/calibre/gui2/widgets.py
+++ b/src/calibre/gui2/widgets.py
@@ -1280,7 +1280,7 @@ class PaperSizes(QComboBox):  # {{{
             from calibre.ebooks.conversion.plugins.pdf_output import PAPER_SIZES
             choices = PAPER_SIZES
         for a in sorted(choices, key=numeric_sort_key):
-            s = getattr(QPageSize, a.capitalize())
+            s = getattr(QPageSize.PageSizeId, a.capitalize())
             sz = QPageSize.definitionSize(s)
             unit = {QPageSize.Unit.Millimeter: 'mm', QPageSize.Unit.Inch: 'inch'}[QPageSize.definitionUnits(s)]
             name = f'{QPageSize.name(s)} ({sz.width():g} x {sz.height():g} {unit})'