diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 8d11a60..b31447d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -24,9 +24,16 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
+  ruff:
+    runs-on: ubuntu-latest
+    timeout-minutes: &timeout-minutes 5
+    steps:
+      - uses: actions/checkout@v6
+      - uses: astral-sh/ruff-action@v4.0.0
+
   mypy:
     runs-on: ${{ matrix.os }}
-    timeout-minutes: &timeout-minutes 5
+    timeout-minutes: *timeout-minutes
     strategy:
       # mypy is os and python-version sensitive. Test on all supported combinations
       matrix:
@@ -42,3 +49,52 @@ jobs:
           activate-environment: true
       - run: uv sync --locked
       - run: mypy . --python-version=${{ matrix.python-version }}
+
+  tests:
+    runs-on: ${{ matrix.os }}
+    timeout-minutes: *timeout-minutes
+    strategy:
+      # Test on all supported runtime combinations
+      matrix:
+        # Arm runners are faster (as long as the same wheels are available)
+        # This project doesn't have any code that should act differently per architecture
+        os: [windows-11-arm, ubuntu-24.04-arm, macos-latest]
+        # TODO: Run tests in parallel on free-threaded python to catch free-threading issues
+        # See: https://py-free-threading.github.io/testing/
+        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13", "3.14"]
+      fail-fast: false
+    steps:
+      - uses: actions/checkout@v6
+      - name: Install Linux Packages
+        if: ${{ startsWith(matrix.os, 'ubuntu') }}
+        run: |
+          # xvfb+openbox: headless X server and WM
+          # x11-xserver-utils (xrandr/xset): required by tests for window geometry
+          sudo apt install -y xvfb openbox x11-xserver-utils
+      - uses: astral-sh/setup-uv@v8.2.0
+        with:
+          python-version: ${{ matrix.python-version }}
+          activate-environment: true
+      - run: uv sync --locked
+      - name: Run tests (Linux)
+        if: ${{ startsWith(matrix.os, 'ubuntu') }}
+        working-directory: tests
+        run: xvfb-run --server-args="-screen 0 1280x1024x24" bash -c "openbox & sleep 1 && python test_pymonctl.py"
+      - name: Run tests (Windows & macOS)
+        if: ${{ !startsWith(matrix.os, 'ubuntu') }}
+        working-directory: tests
+        run: python test_pymonctl.py
+
+  sphinx:
+    runs-on: ubuntu-24.04-arm # Keep in sync with build.os in .readthedocs.yaml
+    timeout-minutes: *timeout-minutes
+    steps:
+      - uses: actions/checkout@v6
+      - uses: astral-sh/setup-uv@v8.2.0
+        with:
+          python-version: "3.14" # Keep in sync with build.tools.python in .readthedocs.yaml
+          activate-environment: true
+      - run: uv sync --locked --no-default-groups --group=docs
+      - name: Build docs
+        # TODO: Add --fail-on-warning, but still too many warnings right now
+        run: sphinx-build --keep-going --builder html docs/source docs/_build/html
diff --git a/pyproject.toml b/pyproject.toml
index 82fdfd7..f9d9788 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -61,6 +61,7 @@ dependencies = [
 docs = ["myst-parser"]
 dev = [
     { include-group = "docs" },
+    "ruff>=0.15.16",
     "ewmhlib",
     "mypy>=0.990,<2",
     "types-python-xlib>=0.32",
diff --git a/ruff.toml b/ruff.toml
new file mode 100644
index 0000000..6cbc1bb
--- /dev/null
+++ b/ruff.toml
@@ -0,0 +1,95 @@
+[lint]
+future-annotations = true
+# https://docs.astral.sh/ruff/rules/
+extend-select = [
+  "ANN2", # flake8-annotations: missing-return-type
+  "C4", # flake8-comprehensions
+  "F401", # unused-import
+  "F404", # late-future-import
+  "FA", # flake8-future-annotations
+  "FLY", # Flynt
+  "ICN", # flake8-import-conventions
+  "PERF", # Perflint
+  "PGH", # pygrep-hooks (blanket-* rules)
+  "PYI", # flake8-pyi
+  "RUF", # Ruff-specific rules
+  "SIM9", # flake8-simplify: split-static-string + zip-dict-keys-and-values
+  "SLOT", # flake8-slots
+  "TC", # flake8-type-checking
+  "TID", # flake8-tidy-imports
+  "UP", # pyupgrade
+  "YTT", # flake8-2020
+]
+ignore = [
+  # Only enforce return types on public functions. Where otherwise mypy infers as Any
+  # Still worth running `ruff check --fix --select=202` once in a while for autofixes
+  "ANN202", # missing-return-type-private-function
+  # Explicit is preferred
+  "UP015", # redundant-open-modes, 
+  # Autofixes print-f style formatting to f-strings,
+  # which is sometimes simpler, but looses template code reading semantics
+  "UP032", # f-string
+  # TC helps prevent circular imports, reduce runtime cost of typing symbols,
+  # and prevent leaking implementations details into modules
+  # However stdlib is not at risk of circular import, is clearly not public API,
+  # and assume it's gonna be included in the import chain at some point anyway
+  "TC003", # typing-only-standard-library-import
+  # Typeshed doesn't want complex or non-literal defaults for maintenance and testing reasons.
+  # This doesn't affect us, let's have more complete stubs.
+  "PYI011", # typed-argument-default-in-stub
+  "PYI014", # argument-default-in-stub
+  "PYI053", # string-or-bytes-too-long
+  # Good to watch for, but often unfixable
+  # Anyway Python 3.11 introduced "zero cost" exception handling
+  "PERF203", # try-except-in-loop,
+
+  # TODO: Add and configure isort (I) first
+  "RUF022",
+
+  # TODO: Consider later
+  "UP031", # printf-string-formatting
+  "RUF059", # unused-unpacked-variable
+
+  # TODO: Not autofixable, address in a separate PR !
+  "E402",
+  "E722",
+  "F401",
+  "PERF401",
+  "PYI063",
+  "RUF003",
+  "RUF012",
+  "RUF022",
+]
+# F401 would remove imports not marked as explicit re-exports, which may break API boundaries
+extend-unsafe-fixes = ["F401"]
+
+[lint.per-file-ignores]
+"**/typings/**/*.pyi" = [
+  "E402", # https://github.com/astral-sh/ruff/issues/26160
+  "F811", # Re-exports false positives
+  # The following can't be controlled for external libraries:
+  "A", # Shadowing builtin names
+  "E741", # ambiguous variable name
+  "F403", # `from . import *` used; unable to detect undefined names
+  "FBT", # flake8-boolean-trap
+  "ICN001", # unconventional-import-alias
+  "N8", # Naming conventions
+  "PLC2701", # Private name import
+  "PLE0302", # The special method expects a given signature
+  "PLR0904", # Too many public methods
+  "PLR0913", # Argument count
+  "PLR0917", # Too many positional arguments
+  "PLW3201", # misspelled dunder method name
+  "SLOT", # flake8-slots
+  # Stubs can sometimes re-export entire modules.
+  # Issues with using a star-imported name will be caught by type-checkers.
+  "F405", # may be undefined, or defined from star imports
+  # It's normal to be missing annotations for local stubs.
+  # If they were complete, we'd upload them to typeshed!
+  "ANN0",
+  "ANN2",
+]
+
+# https://docs.astral.sh/ruff/settings/#lintflake8-type-checking
+[lint.flake8-type-checking]
+quote-annotations = true
diff --git a/src/pymonctl/__init__.py b/src/pymonctl/__init__.py
index 396d267..c8592b9 100644
--- a/src/pymonctl/__init__.py
+++ b/src/pymonctl/__init__.py
@@ -1,5 +1,4 @@
 #!/usr/bin/python
-# -*- coding: utf-8 -*-
 from importlib.metadata import version as _importlib_version
 
 __all__ = [
diff --git a/src/pymonctl/_main.py b/src/pymonctl/_main.py
index 1cd6dcd..a4fdaa4 100644
--- a/src/pymonctl/_main.py
+++ b/src/pymonctl/_main.py
@@ -1,15 +1,20 @@
 #!/usr/bin/python
-# -*- coding: utf-8 -*-
 from __future__ import annotations
 
 import sys
 import threading
 from abc import abstractmethod, ABC
 from collections.abc import Callable
-from typing import List, Optional, Union, Tuple, cast
+from typing import TYPE_CHECKING
 
 from ._structs import DisplayMode, ScreenValue, Size, Point, Box, Rect, Position, Orientation
 
+if TYPE_CHECKING:
+    from Xlib.ext import randr
+    from Xlib.protocol.rq import Struct
+    from Xlib.xobject.drawable import Window as XWindow
+    import Xlib.display
+
 
 def _pointInBox(x: int, y: int, left: int, top: int, width: int, height: int) -> bool:
     """Returns ``True`` if the ``(x, y)`` point is within the box described
@@ -77,7 +82,7 @@ def getAllMonitorsDict() -> dict[str, ScreenValue]:
         return _updateScreens.getScreens()
 
 
-def getMonitorsData(handle: Optional[int] = None):
+def getMonitorsData(handle: int | None = None):
     # Linux ONLY since X11 is not thread-safe (randr crashes when querying in parallel from separate thread)
     if sys.platform == "linux":
         if _updateScreens is None:
@@ -105,7 +110,7 @@ def getPrimary() -> Monitor:
     return _getPrimary()
 
 
-def findMonitorsAtPoint(x: int, y: int) -> List[Monitor]:
+def findMonitorsAtPoint(x: int, y: int) -> list[Monitor]:
     """
     Get all Monitor class instances in which given coordinates (x, y) are found.
 
@@ -116,7 +121,7 @@ def findMonitorsAtPoint(x: int, y: int) -> List[Monitor]:
     return _findMonitor(x, y)
 
 
-def findMonitorsAtPointInfo(x: int, y: int) -> List[dict[str, ScreenValue]]:
+def findMonitorsAtPointInfo(x: int, y: int) -> list[dict[str, ScreenValue]]:
     """
     Get all monitors info in which given coordinates (x, y) are found.
 
@@ -124,7 +129,7 @@ def findMonitorsAtPointInfo(x: int, y: int) -> List[dict[str, ScreenValue]]:
     :param y: target Y coordinate
     :return: list of monitor info (see getAllMonitorsDict() doc) as a list of dicts, or empty
     """
-    info: List[dict[str, ScreenValue]] = [{}]
+    info: list[dict[str, ScreenValue]] = [{}]
     monitors = getAllMonitorsDict()
     for monitor in monitors.keys():
         pos = monitors[monitor]["position"]
@@ -134,7 +139,7 @@ def findMonitorsAtPointInfo(x: int, y: int) -> List[dict[str, ScreenValue]]:
     return info
 
 
-def findMonitorWithName(name: str) -> Optional[Monitor]:
+def findMonitorWithName(name: str) -> Monitor | None:
     """
     Get the Monitor class instance which name matches given name.
 
@@ -164,7 +169,7 @@ def findMonitorWithNameInfo(name: str) -> dict[str, ScreenValue]:
     return info
 
 
-def arrangeMonitors(arrangement: dict[str, dict[str, Optional[Union[str, int, Position, Point, Size]]]]):
+def arrangeMonitors(arrangement: dict[str, dict[str, str | int | Position | Point | Size | None]]):
     """
     Arrange all monitors in a given shape.
 
@@ -197,7 +202,7 @@ def arrangeMonitors(arrangement: dict[str, dict[str, Optional[Union[str, int, Po
     _arrangeMonitors(arrangement)
 
 
-def saveSetup() -> List[Tuple[Monitor, ScreenValue]]:
+def saveSetup() -> list[tuple[Monitor, ScreenValue]]:
     """
     Save current monitors setup information to be restored afterward.
 
@@ -207,14 +212,14 @@ def saveSetup() -> List[Tuple[Monitor, ScreenValue]]:
 
     :return: list of tuples containing all necessary info to restore saved setup as required by restoreSetup()
     """
-    result: List[Tuple[Monitor, ScreenValue]] = []
+    result: list[tuple[Monitor, ScreenValue]] = []
     monDict: dict[str, ScreenValue] = getAllMonitorsDict()
     for monName in monDict.keys():
         result.append((Monitor(monDict[monName]["id"]), monDict[monName]))
     return result
 
 
-def restoreSetup(setup: List[Tuple[Monitor, ScreenValue]]):
+def restoreSetup(setup: list[tuple[Monitor, ScreenValue]]):
     """
     Restore given monitors setup (position, mode, orientation, scale, etc.). The function will also
     try to re-attach / turn on / wake monitors if needed.
@@ -223,7 +228,7 @@ def restoreSetup(setup: List[Tuple[Monitor, ScreenValue]]):
 
     :param setup: monitors info dictionary as returned by saveSetup()
     """
-    arrangement: dict[str, dict[str, Optional[Union[str, int, Position, Point, Size]]]] = {}
+    arrangement: dict[str, dict[str, str | int | Position | Point | Size | None]] = {}
     for monData in setup:
         monitor, monDict = monData
         if not monitor.isAttached:
@@ -258,7 +263,7 @@ class BaseMonitor(ABC):
 
     @property
     @abstractmethod
-    def size(self) -> Optional[Size]:
+    def size(self) -> Size | None:
         """
         Get the dimensions of the monitor as a size struct (width, height)
 
@@ -271,7 +276,7 @@ def size(self) -> Optional[Size]:
 
     @property
     @abstractmethod
-    def workarea(self) -> Optional[Rect]:
+    def workarea(self) -> Rect | None:
         """
         Get dimensions of the "usable by applications" area (screen size minus docks, taskbars and so on), as
         a rect struct (x, y, right, bottom)
@@ -284,7 +289,7 @@ def workarea(self) -> Optional[Rect]:
 
     @property
     @abstractmethod
-    def position(self) -> Optional[Point]:
+    def position(self) -> Point | None:
         """
         Get monitor position coordinates as a point struct (x, y)
 
@@ -295,7 +300,7 @@ def position(self) -> Optional[Point]:
         raise NotImplementedError
 
     @abstractmethod
-    def setPosition(self, relativePos: Union[int, Position, Point, Tuple[int, int]], relativeTo: Optional[str]):
+    def setPosition(self, relativePos: int | Position | Point | tuple[int, int], relativeTo: str | None):
         """
         Change relative position of the current the monitor in relation to another existing monitor (e.g. primary monitor).
 
@@ -320,7 +325,7 @@ def setPosition(self, relativePos: Union[int, Position, Point, Tuple[int, int]],
 
     @property
     @abstractmethod
-    def box(self) -> Optional[Box]:
+    def box(self) -> Box | None:
         """
         Get monitor dimensions as a box struct (x, y, width, height)
 
@@ -332,7 +337,7 @@ def box(self) -> Optional[Box]:
 
     @property
     @abstractmethod
-    def rect(self) -> Optional[Rect]:
+    def rect(self) -> Rect | None:
         """
         Get monitor dimensions as a rect struct (x, y, right, bottom)
 
@@ -344,7 +349,7 @@ def rect(self) -> Optional[Rect]:
 
     @property
     @abstractmethod
-    def scale(self) -> Optional[Tuple[float, float]]:
+    def scale(self) -> tuple[float, float] | None:
         """
         Get scale for the monitor
 
@@ -355,7 +360,7 @@ def scale(self) -> Optional[Tuple[float, float]]:
         raise NotImplementedError
 
     @abstractmethod
-    def setScale(self, scale: Tuple[float, float], applyGlobally: bool = True):
+    def setScale(self, scale: tuple[float, float], applyGlobally: bool = True):
         """
         Change scale for the monitor
 
@@ -368,7 +373,7 @@ def setScale(self, scale: Tuple[float, float], applyGlobally: bool = True):
 
     @property
     @abstractmethod
-    def dpi(self) -> Optional[Tuple[float, float]]:
+    def dpi(self) -> tuple[float, float] | None:
         """
         Get the dpi (dots/pixels per inch) value for the monitor
 
@@ -380,7 +385,7 @@ def dpi(self) -> Optional[Tuple[float, float]]:
 
     @property
     @abstractmethod
-    def orientation(self) -> Optional[Union[int, Orientation]]:
+    def orientation(self) -> int | Orientation | None:
         """
         Get current orientation for the monitor identified by name (or primary if empty)
 
@@ -395,7 +400,7 @@ def orientation(self) -> Optional[Union[int, Orientation]]:
         raise NotImplementedError
 
     @abstractmethod
-    def setOrientation(self, orientation: Optional[Union[int, Orientation]]):
+    def setOrientation(self, orientation: int | Orientation | None):
         """
         Change orientation for the monitor identified by name (or primary if empty)
 
@@ -411,7 +416,7 @@ def setOrientation(self, orientation: Optional[Union[int, Orientation]]):
 
     @property
     @abstractmethod
-    def frequency(self) -> Optional[float]:
+    def frequency(self) -> float | None:
         """
         Get current refresh rate of monitor.
 
@@ -424,7 +429,7 @@ def frequency(self) -> Optional[float]:
 
     @property
     @abstractmethod
-    def colordepth(self) -> Optional[int]:
+    def colordepth(self) -> int | None:
         """
         Get the colordepth (bits per pixel to describe color) value for the monitor
 
@@ -436,7 +441,7 @@ def colordepth(self) -> Optional[int]:
 
     @property
     @abstractmethod
-    def brightness(self) -> Optional[int]:
+    def brightness(self) -> int | None:
         """
         Get the brightness of monitor. The return value is normalized to 0-100 (as a percentage)
 
@@ -445,7 +450,7 @@ def brightness(self) -> Optional[int]:
         raise NotImplementedError
 
     @abstractmethod
-    def setBrightness(self, brightness: Optional[int]):
+    def setBrightness(self, brightness: int | None):
         """
         Change the brightness of monitor. The input parameter must be defined as a percentage (0-100)
 
@@ -455,7 +460,7 @@ def setBrightness(self, brightness: Optional[int]):
 
     @property
     @abstractmethod
-    def contrast(self) -> Optional[int]:
+    def contrast(self) -> int | None:
         """
         Get the contrast of monitor. The return value is normalized to 0-100 (as a percentage)
 
@@ -466,7 +471,7 @@ def contrast(self) -> Optional[int]:
         raise NotImplementedError
 
     @abstractmethod
-    def setContrast(self, contrast: Optional[int]):
+    def setContrast(self, contrast: int | None):
         """
         Change the contrast of monitor. The input parameter must be defined as a percentage (0-100)
 
@@ -480,7 +485,7 @@ def setContrast(self, contrast: Optional[int]):
 
     @property
     @abstractmethod
-    def mode(self) -> Optional[DisplayMode]:
+    def mode(self) -> DisplayMode | None:
         """
         Get the current monitor mode (width, height, refresh-rate) for the monitor
 
@@ -489,7 +494,7 @@ def mode(self) -> Optional[DisplayMode]:
         raise NotImplementedError
 
     @abstractmethod
-    def setMode(self, mode: Optional[DisplayMode]):
+    def setMode(self, mode: DisplayMode | None):
         """
         Change current monitor mode (resolution and/or refresh-rate) for the monitor
 
@@ -501,7 +506,7 @@ def setMode(self, mode: Optional[DisplayMode]):
 
     @property
     @abstractmethod
-    def defaultMode(self) -> Optional[DisplayMode]:
+    def defaultMode(self) -> DisplayMode | None:
         """
         Get the preferred mode for the monitor
 
@@ -571,7 +576,7 @@ def turnOff(self):
 
     @property
     @abstractmethod
-    def isOn(self) -> Optional[bool]:
+    def isOn(self) -> bool | None:
         """
         Check if monitor is on
 
@@ -602,7 +607,7 @@ def suspend(self):
 
     @property
     @abstractmethod
-    def isSuspended(self) -> Optional[bool]:
+    def isSuspended(self) -> bool | None:
         """
         Check if monitor is in standby mode
 
@@ -642,7 +647,7 @@ def detach(self, permanent: bool = False):
 
     @property
     @abstractmethod
-    def isAttached(self) -> Optional[bool]:
+    def isAttached(self) -> bool | None:
         """
         Check if monitor is attached (not necessarily ON) to system
 
@@ -652,26 +657,22 @@ def isAttached(self) -> Optional[bool]:
 
 
 _updateRequested = False
-_plugListeners: List[Callable[[List[str], dict[str, ScreenValue]], None]] = []
-_changeListeners: List[Callable[[List[str], dict[str, ScreenValue]], None]] = []
+_plugListeners: list[Callable[[list[str], dict[str, ScreenValue]], None]] = []
+_changeListeners: list[Callable[[list[str], dict[str, ScreenValue]], None]] = []
 _kill = threading.Event()
 _interval = 0.5
 
 
 class _UpdateScreens(threading.Thread):
 
-    def __init__(self, kill: threading.Event, interval: float = 0.5):
+    def __init__(self, kill: threading.Event, interval: float = 0.5) -> None:
         threading.Thread.__init__(self)
 
         self._kill = kill
         self._interval = interval
         self._screens: dict[str, ScreenValue] = {}
         if sys.platform == "linux":
-            import Xlib.display
-            from Xlib.ext import randr
-            from Xlib.protocol.rq import Struct
-            from Xlib.xobject.drawable import Window as XWindow
-            self._monitorsData: List[Tuple[Xlib.display.Display, Struct, XWindow,randr.GetScreenResourcesCurrent,
+            self._monitorsData: list[tuple[Xlib.display.Display, Struct, XWindow,randr.GetScreenResourcesCurrent,
                                                      randr.MonitorInfo, str, int, randr.GetOutputInfo,
                                                      int, randr.GetCrtcInfo]] = []
             self._screens, self._monitorsData = _getAllMonitorsDictThread()
@@ -758,7 +759,7 @@ def getMonitorsData(self, handle):
         return self._monitorsData
 
 
-_updateScreens: Optional[_UpdateScreens] = None
+_updateScreens: _UpdateScreens | None = None
 
 
 def enableUpdateInfo():
@@ -794,7 +795,7 @@ def disableUpdateInfo():
         _killUpdateScreens()
 
 
-def plugListenerRegister(monitorCountChanged: Callable[[List[str], dict[str, ScreenValue]], None]):
+def plugListenerRegister(monitorCountChanged: Callable[[list[str], dict[str, ScreenValue]], None]):
     """
     Use this only if you need to keep track of monitor that can be dynamically plugged or unplugged in a
     multi-monitor setup.
@@ -815,7 +816,7 @@ def plugListenerRegister(monitorCountChanged: Callable[[List[str], dict[str, Scr
         _startUpdateScreens()
 
 
-def plugListenerUnregister(monitorCountChanged: Callable[[List[str], dict[str, ScreenValue]], None]):
+def plugListenerUnregister(monitorCountChanged: Callable[[list[str], dict[str, ScreenValue]], None]):
     """
     Use this function to un-register your custom callback. The callback will not be invoked anymore in case
     the number of monitor changes.
@@ -834,7 +835,7 @@ def plugListenerUnregister(monitorCountChanged: Callable[[List[str], dict[str, S
         _killUpdateScreens()
 
 
-def changeListenerRegister(monitorPropsChanged: Callable[[List[str], dict[str, ScreenValue]], None]):
+def changeListenerRegister(monitorPropsChanged: Callable[[list[str], dict[str, ScreenValue]], None]):
     """
     Use this only if you need to keep track of monitor properties changes (position, size, refresh-rate, etc.) in a
     multi-monitor setup.
@@ -855,7 +856,7 @@ def changeListenerRegister(monitorPropsChanged: Callable[[List[str], dict[str, S
         _startUpdateScreens()
 
 
-def changeListenerUnregister(monitorPropsChanged: Callable[[List[str], dict[str, ScreenValue]], None]):
+def changeListenerUnregister(monitorPropsChanged: Callable[[list[str], dict[str, ScreenValue]], None]):
     """
     Use this function to un-register your custom callback. The callback will not be invoked anymore in case
     the monitor properties change.
@@ -916,7 +917,7 @@ def isUpdateInfoEnabled() -> bool:
     return _updateRequested
 
 
-def isPlugListenerRegistered(monitorCountChanged: Callable[[List[str], dict[str, ScreenValue]], None]):
+def isPlugListenerRegistered(monitorCountChanged: Callable[[list[str], dict[str, ScreenValue]], None]):
     """
     Check if callback is already registered to be invoked when monitor plugged count change
 
@@ -926,7 +927,7 @@ def isPlugListenerRegistered(monitorCountChanged: Callable[[List[str], dict[str,
     return monitorCountChanged in _plugListeners
 
 
-def isChangeListenerRegistered(monitorPropsChanged: Callable[[List[str], dict[str, ScreenValue]], None]):
+def isChangeListenerRegistered(monitorPropsChanged: Callable[[list[str], dict[str, ScreenValue]], None]):
     """
     Check if callback is already registered to be invoked when monitor properties change
 
@@ -956,7 +957,7 @@ def updateWatchdogInterval(interval: float):
         _interval = interval
 
 
-def _getRelativePosition(monitor, relativeTo) -> Tuple[int, int]:
+def _getRelativePosition(monitor, relativeTo) -> tuple[int, int]:
     relPos = monitor["relativePos"]
     if relPos == Position.PRIMARY:
         x = y = 0
diff --git a/src/pymonctl/_pymonctl_linux.py b/src/pymonctl/_pymonctl_linux.py
index afc00fd..129ce2a 100644
--- a/src/pymonctl/_pymonctl_linux.py
+++ b/src/pymonctl/_pymonctl_linux.py
@@ -1,5 +1,4 @@
 #!/usr/bin/python
-# -*- coding: utf-8 -*-
 from __future__ import annotations
 
 import sys
@@ -11,20 +10,22 @@
 import subprocess
 import threading
 
-from typing import Optional, List, Union, Tuple, NamedTuple
+from typing import NamedTuple, TYPE_CHECKING
 
 import Xlib.display
 import Xlib.X
 import Xlib.protocol
 import Xlib.xobject
-from Xlib.protocol.rq import Struct
-from Xlib.xobject.drawable import Window as XWindow
 from Xlib.ext import randr
 
 from ._main import BaseMonitor, _pointInBox, _getRelativePosition, getMonitorsData, isWatchdogEnabled, \
                    DisplayMode, ScreenValue, Box, Rect, Point, Size, Position, Orientation
 from ewmhlib import defaultEwmhRoot, getProperty, getPropertyValue, getRoots, Props
 
+if TYPE_CHECKING:
+    from Xlib.protocol.rq import Struct
+    from Xlib.xobject.drawable import Window as XWindow
+
 
 def _getAllMonitors() -> list[LinuxMonitor]:
     return [LinuxMonitor(monitor.crtcs[0]) for monitor in _XgetMonitors()]
@@ -41,12 +42,12 @@ def _getAllMonitorsDict() -> dict[str, ScreenValue]:
     return monitorsDict
 
 
-def _getAllMonitorsDictThread() -> (Tuple[dict[str, ScreenValue],
-                                          List[Tuple[Xlib.display.Display, Struct, XWindow, randr.GetScreenResourcesCurrent,
+def _getAllMonitorsDictThread() -> (tuple[dict[str, ScreenValue],
+                                          list[tuple[Xlib.display.Display, Struct, XWindow, randr.GetScreenResourcesCurrent,
                                                      randr.MonitorInfo, str, int, randr.GetOutputInfo, int, randr.GetCrtcInfo]]]):
     # display connections seem to fail when shared amongst threads and/or queried too quickly in parallel
     monitorsDict: dict[str, ScreenValue] = {}
-    monitorsData: List[Tuple[Xlib.display.Display, Struct, XWindow, randr.GetScreenResourcesCurrent,
+    monitorsData: list[tuple[Xlib.display.Display, Struct, XWindow, randr.GetScreenResourcesCurrent,
                              randr.MonitorInfo, str, int, randr.GetOutputInfo, int, randr.GetCrtcInfo]] = []
     for monitorData in _getMonitorsData():
         display, screen, root, res, monitor, monName, output, outputInfo, crtc, crtcInfo = monitorData
@@ -59,7 +60,7 @@ def _buildMonitorsDict(display, screen, root, res, monitor, monName, output, out
 
     is_primary = monitor.primary == 1
     x, y, w, h = monitor.x, monitor.y, monitor.width_in_pixels, monitor.height_in_pixels
-    wa: List[int] = getPropertyValue(getProperty(window=root, prop=Props.Root.WORKAREA, display=display),
+    wa: list[int] = getPropertyValue(getProperty(window=root, prop=Props.Root.WORKAREA, display=display),
                                      display=display)
     # Thanks to odknt (https://github.com/odknt) for his HELP!!!
     if isinstance(wa, list) and len(wa) >= 4:
@@ -105,7 +106,7 @@ def _getMonitorsCount() -> int:
     return len(_XgetMonitors())
 
 
-def _findMonitor(x: int, y: int) -> List[LinuxMonitor]:
+def _findMonitor(x: int, y: int) -> list[LinuxMonitor]:
     monitors = []
     for monitor in _XgetMonitors():
         if _pointInBox(x, y, monitor.x, monitor.y, monitor.width_in_pixels, monitor.height_in_pixels):
@@ -117,7 +118,7 @@ def _getPrimary() -> LinuxMonitor:
     return LinuxMonitor()
 
 
-def _arrangeMonitors(arrangement: dict[str, dict[str, Optional[Union[str, int, Position, Point, Size]]]]):
+def _arrangeMonitors(arrangement: dict[str, dict[str, str | int | Position | Point | Size | None]]):
 
     monitors = _XgetMonitorsDict()
     setAsPrimary = ""
@@ -131,7 +132,7 @@ def _arrangeMonitors(arrangement: dict[str, dict[str, Optional[Union[str, int, P
         elif relPos == Position.PRIMARY or relPos == (0, 0) or relPos == Point(0, 0):
             setAsPrimary = monName
 
-    newArrangement: dict[str, dict[str, Union[int, bool]]] = {}
+    newArrangement: dict[str, dict[str, int | bool]] = {}
     newPos: dict[str, dict[str, int]] = {}
     xOffset = yOffset = 0
 
@@ -151,7 +152,7 @@ def _arrangeMonitors(arrangement: dict[str, dict[str, Optional[Union[str, int, P
     for monName in arrangement.keys():
 
         arrInfo = arrangement[monName]
-        relativePos: Union[Position, int, Point, Tuple[int, int]] = arrInfo["relativePos"]
+        relativePos: Position | int | Point | tuple[int, int] = arrInfo["relativePos"]
         targetMonInfo = monitors[monName]["monitor"]
         setPrimary = not setAsPrimary and targetMonInfo.primary == 1
 
@@ -215,7 +216,7 @@ def _getMousePos() -> Point:
 
 class LinuxMonitor(BaseMonitor):
 
-    def __init__(self, handle: Optional[int] = None):
+    def __init__(self, handle: int | None = None) -> None:
         """
         Class to access all methods and functions to get info and manage monitors plugged to the system.
 
@@ -231,7 +232,7 @@ def __init__(self, handle: Optional[int] = None):
             raise ValueError
 
     @property
-    def size(self) -> Optional[Size]:
+    def size(self) -> Size | None:
         monitors = _XgetMonitors(self.name)
         if monitors:
             monitor = monitors[0]
@@ -239,9 +240,9 @@ def size(self) -> Optional[Size]:
         return None
 
     @property
-    def workarea(self) -> Optional[Rect]:
+    def workarea(self) -> Rect | None:
         # https://askubuntu.com/questions/1124149/how-to-get-taskbar-size-and-position-with-python
-        wa: List[int] = getPropertyValue(
+        wa: list[int] = getPropertyValue(
             getProperty(window=self.root, prop=Props.Root.WORKAREA, display=self.display), display=self.display)
         if wa:
             wx, wy, wr, wb = wa[0], wa[1], wa[2], wa[3]
@@ -249,16 +250,16 @@ def workarea(self) -> Optional[Rect]:
         return None
 
     @property
-    def position(self) -> Optional[Point]:
+    def position(self) -> Point | None:
         monitors = _XgetMonitors(self.name)
         if monitors:
             monitor = monitors[0]
             return Point(monitor.x, monitor.y)
         return None
 
-    def setPosition(self, relativePos: Union[int, Position, Point, Tuple[int, int]], relativeTo: Optional[str]):
+    def setPosition(self, relativePos: int | Position | Point | tuple[int, int], relativeTo: str | None):
         # https://askubuntu.com/questions/1193940/setting-monitor-scaling-to-200-with-xrandr
-        arrangement: dict[str, dict[str, Optional[Union[str, int, Position, Point, Tuple[int, int]]]]] = {}
+        arrangement: dict[str, dict[str, str | int | Position | Point | tuple[int, int] | None]] = {}
         monitors: dict[str, dict[str, randr.MonitorInfo]] = _XgetMonitorsDict()
         monKeys = list(monitors.keys())
         if relativePos == Position.PRIMARY:
@@ -295,7 +296,7 @@ def setPosition(self, relativePos: Union[int, Position, Point, Tuple[int, int]],
         _arrangeMonitors(arrangement) # type: ignore[arg-type]
 
     @property
-    def box(self) -> Optional[Box]:
+    def box(self) -> Box | None:
         monitors = _XgetMonitors(self.name)
         if monitors:
             monitor = monitors[0]
@@ -303,7 +304,7 @@ def box(self) -> Optional[Box]:
         return None
 
     @property
-    def rect(self) -> Optional[Rect]:
+    def rect(self) -> Rect | None:
         monitors = _XgetMonitors(self.name)
         if monitors:
             monitor = monitors[0]
@@ -311,10 +312,10 @@ def rect(self) -> Optional[Rect]:
         return None
 
     @property
-    def scale(self) -> Optional[Tuple[float, float]]:
+    def scale(self) -> tuple[float, float] | None:
         return _scale(self.name)
 
-    def setScale(self, scale: Optional[Tuple[float, float]], applyGlobally: bool = True):
+    def setScale(self, scale: tuple[float, float] | None, applyGlobally: bool = True):
         # https://askubuntu.com/questions/1193940/setting-monitor-scaling-to-200-with-xrandr
         # https://wiki.archlinux.org/title/HiDPI#GNOME
         cmd = ""
@@ -335,7 +336,7 @@ def setScale(self, scale: Optional[Tuple[float, float]], applyGlobally: bool = T
             if cmd:
                 _, _ = _runProc(cmd)
 
-    def _buildScaleCmd(self, scale: Tuple[float, float]) -> str:
+    def _buildScaleCmd(self, scale: tuple[float, float]) -> str:
         # https://unix.stackexchange.com/questions/596887/how-to-scale-the-resolution-display-of-the-desktop-and-or-applications
         scaleX, scaleY = scale
         cmd = ""
@@ -372,11 +373,11 @@ def _buildScaleCmd(self, scale: Tuple[float, float]) -> str:
         return cmd
 
     @property
-    def dpi(self) -> Optional[Tuple[float, float]]:
+    def dpi(self) -> tuple[float, float] | None:
         monitors = _XgetMonitors(self.name)
         if monitors:
             monitor = monitors[0]
-            x, y, w, h = monitor.x, monitor.y, monitor.width_in_pixels, monitor.height_in_pixels
+            _x, _y, w, h = monitor.x, monitor.y, monitor.width_in_pixels, monitor.height_in_pixels
             if monitor.width_in_millimeters != 0 and monitor.height_in_millimeters != 0:
                 dpiX, dpiY = round((w * 25.4) / monitor.width_in_millimeters), round((h * 25.4) / monitor.height_in_millimeters)
             else:
@@ -385,7 +386,7 @@ def dpi(self) -> Optional[Tuple[float, float]]:
         return None
 
     @property
-    def orientation(self) -> Optional[Union[int, Orientation]]:
+    def orientation(self) -> int | Orientation | None:
         monitorData = getMonitorsData(self.handle)
         if monitorData:
             display, screen, root, res, monitor, monName, output, outputInfo, crtc, crtcInfo = monitorData[0]
@@ -394,7 +395,7 @@ def orientation(self) -> Optional[Union[int, Orientation]]:
                 return Orientation(int(math.log(crtcInfo.rotation, 2)))
         return None
 
-    def setOrientation(self, orientation: Optional[Union[int, Orientation]]):
+    def setOrientation(self, orientation: int | Orientation | None):
         if orientation is not None and orientation in (Orientation.NORMAL, Orientation.INVERTED, Orientation.LEFT, Orientation.RIGHT):
             global _rotations
             direction = _rotations[orientation]
@@ -402,7 +403,7 @@ def setOrientation(self, orientation: Optional[Union[int, Orientation]]):
             _, _ = _runProc(cmd)
 
     @property
-    def frequency(self) -> Optional[float]:
+    def frequency(self) -> float | None:
         monitorData = getMonitorsData(self.handle)
         if monitorData:
             display, screen, root, res, monitor, monName, output, outputInfo, crtc, crtcInfo = monitorData[0]
@@ -420,7 +421,7 @@ def colordepth(self) -> int:
         return int(self.screen.root_depth)
 
     @property
-    def brightness(self) -> Optional[int]:
+    def brightness(self) -> int | None:
         # https://manerosss.wordpress.com/2017/05/16/brightness-linux-xrandr/
         value = None
         cmd = 'xrandr --verbose | grep %s -A 10 | grep "Brightness" | grep -o "[0-9].*"' % self.name
@@ -432,7 +433,7 @@ def brightness(self) -> Optional[int]:
                 pass
         return value
 
-    def setBrightness(self, brightness: Optional[int]):
+    def setBrightness(self, brightness: int | None):
         if brightness is not None and 0 <= brightness <= 100:
             value = brightness / 100
             if 0 <= value <= 1:
@@ -440,7 +441,7 @@ def setBrightness(self, brightness: Optional[int]):
                 _, _ = _runProc(cmd)
 
     @property
-    def contrast(self) -> Optional[int]:
+    def contrast(self) -> int | None:
         value = None
         cmd = 'xrandr --verbose | grep %s -A 10 | grep "Gamma" | grep -o "[0-9].*"' % self.name
         code, ret = _runProc(cmd)
@@ -452,7 +453,7 @@ def contrast(self) -> Optional[int]:
                 pass
         return value
 
-    def setContrast(self, contrast: Optional[int]):
+    def setContrast(self, contrast: int | None):
         if contrast is not None and 0<= contrast <= 100:
             value = contrast / 100
             if 0 <= value <= 1:
@@ -462,7 +463,7 @@ def setContrast(self, contrast: Optional[int]):
                 _, _ = _runProc(cmd)
 
     @property
-    def mode(self) -> Optional[DisplayMode]:
+    def mode(self) -> DisplayMode | None:
         monitorData = getMonitorsData(self.handle)
         if monitorData:
             display, screen, root, res, monitor, monName, output, outputInfo, crtc, crtcInfo = monitorData[0]
@@ -475,7 +476,7 @@ def mode(self) -> Optional[DisplayMode]:
                     return DisplayMode(resMode.width, resMode.height, freq)
         return None
 
-    def setMode(self, mode: Optional[DisplayMode]):
+    def setMode(self, mode: DisplayMode | None):
         # https://stackoverflow.com/questions/12706631/x11-change-resolution-and-make-window-fullscreen
         # randr.set_screen_size(defaultEwmhRoot.root, mode.width, mode.height, 0, 0)
         # randr.set_screen_config(defaultEwmhRoot.root, size_id, 0, 0, round(mode.frequency), 0)
@@ -485,7 +486,7 @@ def setMode(self, mode: Optional[DisplayMode]):
             _, _ = _runProc(cmd)
 
     @property
-    def defaultMode(self) -> Optional[DisplayMode]:
+    def defaultMode(self) -> DisplayMode | None:
         # Assuming first mode is default (perhaps not the best way)
         monitorData = getMonitorsData(self.handle)
         if monitorData:
@@ -506,7 +507,7 @@ def setDefaultMode(self):
 
     @property
     def allModes(self) -> list[DisplayMode]:
-        modes: List[DisplayMode] = []
+        modes: list[DisplayMode] = []
         monitorData = getMonitorsData(self.handle)
         if monitorData:
             display, screen, root, res, monitor, monName, output, outputInfo, crtc, crtcInfo = monitorData[0]
@@ -562,11 +563,11 @@ def turnOff(self):
             _, _ = _runProc(cmd)
 
     @property
-    def isOn(self) -> Optional[bool]:
+    def isOn(self) -> bool | None:
         # https://stackoverflow.com/questions/3433203/how-to-determine-if-lcd-monitor-is-turned-on-from-linux-command-line
         cmd = "xrandr --listactivemonitors"
         code, ret = _runProc(cmd)
-        res: Optional[bool] = None
+        res: bool | None = None
         if ret:
             res = self.name in ret
         isSuspended = self.isSuspended
@@ -579,7 +580,7 @@ def suspend(self):
             _, _ = _runProc(cmd)
 
     @property
-    def isSuspended(self) -> Optional[bool]:
+    def isSuspended(self) -> bool | None:
         cmd = 'xset -q | grep " Monitor is "'
         code, ret = _runProc(cmd)
         if ret:
@@ -618,7 +619,7 @@ def isAttached(self) -> bool:
         return bool(monitor)
 
 
-def _buildCommand(arrangement: dict[str, dict[str, Union[int, bool]]], xOffset: int, yOffset: int):
+def _buildCommand(arrangement: dict[str, dict[str, int | bool]], xOffset: int, yOffset: int):
     cmd = "xrandr"
     for monName in arrangement.keys():
         arrInfo = arrangement[monName]
@@ -632,10 +633,10 @@ def _buildCommand(arrangement: dict[str, dict[str, Union[int, bool]]], xOffset:
     return cmd
 
 
-def _GNOME_isScalingGlobal() -> Optional[bool]:
+def _GNOME_isScalingGlobal() -> bool | None:
     cmd = '''gsettings get org.gnome.mutter experimental-features'''
     try:
-        proc = subprocess.run(cmd, text=True, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        proc = subprocess.run(cmd, text=True, shell=True, capture_output=True)
         if "wayland" in os.environ.get('XDG_SESSION_TYPE', '').lower():
             return bool("scale-monitor-framebuffer" not in proc.stdout)
         else:
@@ -653,7 +654,7 @@ def _GNOME_setGlobalScaling(setGlobal=True):
         cmd = ""
         if "wayland" in os.environ.get('XDG_SESSION_TYPE', '').lower():
             try:
-                proc = subprocess.run("grep -sl mutter /proc/*/maps", text=True, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+                proc = subprocess.run("grep -sl mutter /proc/*/maps", text=True, shell=True, capture_output=True)
                 if "/maps" in proc.stdout:
                     cmd = '''gsettings set org.gnome.mutter experimental-features "['scale-monitor-framebuffer']"'''
             except Exception:
@@ -664,7 +665,7 @@ def _GNOME_setGlobalScaling(setGlobal=True):
             _, _ = _runProc(cmd)
   
                     
-def _GNOME_getScalingFactor() -> Optional[int]:
+def _GNOME_getScalingFactor() -> int | None:
     cmd = '''gsettings get org.gnome.settings-daemon.plugins.xsettings overrides'''
     code, ret = _runProc(cmd)
     if "WindowScalingFactor" in ret:
@@ -774,7 +775,7 @@ def _GNOME_getScalingFactor() -> Optional[int]:
 #     interface.ApplyMonitorsConfig(serial, 1, monConfig, {})
 
 
-def _scale(name: str) -> Optional[Tuple[float, float]]:
+def _scale(name: str) -> tuple[float, float] | None:
     if "gnome" in os.environ.get('XDG_CURRENT_DESKTOP', '').lower() and _GNOME_isScalingGlobal():
         value = _GNOME_getScalingFactor()
         if value is not None:
@@ -788,7 +789,7 @@ def _scale(name: str) -> Optional[Tuple[float, float]]:
         if ret:
             try:
                 res = ret.split(" ")
-                lines: List[str] = list(filter(None, res))
+                lines: list[str] = list(filter(None, res))
                 a, b = lines[0].split("x")
                 w = int(a)
                 h = int(b)
@@ -815,7 +816,7 @@ def _scale(name: str) -> Optional[Tuple[float, float]]:
 def _runProc(cmd: str):
     try:
         # Some commands will take some time to be executed and return required value
-        proc = subprocess.run(cmd, text=True, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE) #, timeout=3)
+        proc = subprocess.run(cmd, text=True, shell=True, capture_output=True) #, timeout=3)
         return proc.returncode, proc.stdout
     except Exception:
         pass
@@ -831,16 +832,16 @@ class _Monitor(NamedTuple):
     height_in_pixels: int
     width_in_millimeters: int
     height_in_millimeters: int
-    crtcs: List[int]
+    crtcs: list[int]
 
 
-def _getMonitorsData(handle: Optional[int] = None) -> (
-                        List[Tuple[Xlib.display.Display, Struct, XWindow, randr.GetScreenResourcesCurrent,
+def _getMonitorsData(handle: int | None = None) -> (
+                        list[tuple[Xlib.display.Display, Struct, XWindow, randr.GetScreenResourcesCurrent,
                         randr.MonitorInfo, str, int, randr.GetOutputInfo, int, randr.GetCrtcInfo]]):
-    monitors: List[Tuple[Xlib.display.Display, Struct, XWindow, randr.GetScreenResourcesCurrent,
+    monitors: list[tuple[Xlib.display.Display, Struct, XWindow, randr.GetScreenResourcesCurrent,
                          randr.MonitorInfo, str, int, randr.GetOutputInfo, int, randr.GetCrtcInfo]] = []
     stopSearching = False
-    roots: List[Tuple[Xlib.display.Display, Struct, XWindow]] = getRoots()
+    roots: list[tuple[Xlib.display.Display, Struct, XWindow]] = getRoots()
     for rootData in roots:
         display, screen, root = rootData
         try:
@@ -880,7 +881,7 @@ def _XgetAllMonitors(name: str = ""):
                 monitors.append((display, screen, root, monitor, monName))
     else:
         stopSearching = False
-        roots: List[Tuple[Xlib.display.Display, Struct, XWindow]] = getRoots()
+        roots: list[tuple[Xlib.display.Display, Struct, XWindow]] = getRoots()
         for rootData in roots:
             display, screen, root = rootData
             try:
@@ -904,7 +905,7 @@ def _XgetAllMonitors(name: str = ""):
 
 def _RgetAllMonitors():
     # Check if this works in actual Cinnamon
-    monitors: List[_Monitor] = []
+    monitors: list[_Monitor] = []
     outputDict = {}
     for outputData in _XgetAllOutputs():
         display, screen, root, output, outputInfo = outputData
@@ -946,9 +947,9 @@ def _RgetMonitorsInfo(activeOnly: bool = True):
 
 
 def _XgetAllOutputs(name: str = ""):
-    outputs: List[Tuple[Xlib.display.Display, Xlib.protocol.rq.Struct, Xlib.xobject.drawable.Window,
+    outputs: list[tuple[Xlib.display.Display, Xlib.protocol.rq.Struct, Xlib.xobject.drawable.Window,
                         int, randr.GetOutputInfo]] = []
-    roots: List[Tuple[Xlib.display.Display, Struct, XWindow]] = getRoots()
+    roots: list[tuple[Xlib.display.Display, Struct, XWindow]] = getRoots()
     for rootData in roots:
         display, screen, root = rootData
         res = randr.get_screen_resources_current(root)
@@ -996,7 +997,7 @@ def _XgetMonitorsDict():
     return monitors
 
 
-def _XgetMonitorData(handle: Optional[int] = None) -> Optional[Tuple[Xlib.display.Display, Struct, XWindow, randr.MonitorInfo, int, str]]:
+def _XgetMonitorData(handle: int | None = None) -> tuple[Xlib.display.Display, Struct, XWindow, randr.MonitorInfo, int, str] | None:
     for monitorData in _XgetAllMonitors():
         display, screen, root, monitor, monName = monitorData
         output = monitor.crtcs[0]
diff --git a/src/pymonctl/_pymonctl_macos.py b/src/pymonctl/_pymonctl_macos.py
index 4b90719..d0c1ef8 100644
--- a/src/pymonctl/_pymonctl_macos.py
+++ b/src/pymonctl/_pymonctl_macos.py
@@ -1,11 +1,9 @@
 #!/usr/bin/python
-# -*- coding: utf-8 -*-
 # Incomplete type stubs for pyobjc
 # mypy: disable_error_code = no-any-return
 from __future__ import annotations
 
 import ctypes
-from ctypes import util
 
 import sys
 assert sys.platform == "darwin"
@@ -13,7 +11,7 @@
 import subprocess
 import threading
 
-from typing import Optional, List, Union, cast, Tuple
+from typing import cast
 
 import AppKit
 import Quartz
@@ -73,7 +71,7 @@ def _getMonitorsCount() -> int:
     return cnt
 
 
-def _findMonitor(x: int, y: int) -> List[MacOSMonitor]:
+def _findMonitor(x: int, y: int) -> list[MacOSMonitor]:
     v, ids, cnt = CG.CGGetDisplaysWithPoint((x, y), 10, None, None)
     return [MacOSMonitor(displayId) for displayId in ids]
 
@@ -82,7 +80,7 @@ def _getPrimary() -> MacOSMonitor:
     return MacOSMonitor()
 
 
-def _arrangeMonitors(arrangement: dict[str, dict[str, Optional[Union[str, int, Position, Point, Size]]]]):
+def _arrangeMonitors(arrangement: dict[str, dict[str, str | int | Position | Point | Size | None]]):
 
     monitors = _NSgetAllMonitorsDict()
     primaryPresent = False
@@ -114,7 +112,7 @@ def _arrangeMonitors(arrangement: dict[str, dict[str, Optional[Union[str, int, P
 
     for monName in arrangement.keys():
 
-        relativePos: Union[Position, int, Point, Tuple[int, int]] = arrangement[monName]["relativePos"]
+        relativePos: Position | int | Point | tuple[int, int] = arrangement[monName]["relativePos"]
 
         if monName != setAsPrimary:
 
@@ -177,7 +175,7 @@ def _getMousePos(flipValues: bool = False) -> Point:
 
 class MacOSMonitor(BaseMonitor):
 
-    def __init__(self, handle: Optional[int] = None):
+    def __init__(self, handle: int | None = None) -> None:
         """
         Class to access all methods and functions to get info and manage monitors plugged to the system.
 
@@ -200,15 +198,15 @@ def __init__(self, handle: Optional[int] = None):
                     break
         if self.screen is not None:
             self.name = _getName(self.handle, self.screen)
-            self._ds: Optional[ctypes.CDLL] = None
+            self._ds: ctypes.CDLL | None = None
             self._useDS = True
-            self._cd: Optional[ctypes.CDLL] = None
+            self._cd: ctypes.CDLL | None = None
             self._useCD = True
-            self._iokit: Optional[ctypes.CDLL] = None
+            self._iokit: ctypes.CDLL | None = None
             self._useIOBrightness = True
             self._useIOOrientation = True
-            self._cf: Optional[ctypes.CDLL] = None
-            self._ioservice: Optional[int] = None
+            self._cf: ctypes.CDLL | None = None
+            self._ioservice: int | None = None
             # In some versions / systems, IOKit may fail
             # v = platform.mac_ver()[0].split(".")
             # self._ver = float(v[0] + "." + v[1])
@@ -216,27 +214,27 @@ def __init__(self, handle: Optional[int] = None):
             raise ValueError
 
     @property
-    def size(self, ) -> Optional[Size]:
+    def size(self, ) -> Size | None:
         size = self.screen.frame().size
         res = Size(int(size.width), int(size.height))
         return res
 
     @property
-    def workarea(self) -> Optional[Rect]:
+    def workarea(self) -> Rect | None:
         wa = self.screen.visibleFrame()
         wx, wy, wr, wb = int(wa.origin.x), int(wa.origin.y), int(wa.size.width), int(wa.size.height)
         res = Rect(wx, wy, wr, wb)
         return res
 
     @property
-    def position(self) -> Optional[Point]:
+    def position(self) -> Point | None:
         origin = self.screen.frame().origin
         res = Point(int(origin.x), int(origin.y))
         return res
 
-    def setPosition(self, relativePos: Union[int, Position, Point, Tuple[int, int]], relativeTo: Optional[str]):
+    def setPosition(self, relativePos: int | Position | Point | tuple[int, int], relativeTo: str | None):
         # https://apple.stackexchange.com/questions/249447/change-display-arrangement-in-os-x-macos-programmatically
-        arrangement: dict[str, dict[str, Optional[Union[str, int, Position, Point, Size]]]] = {}
+        arrangement: dict[str, dict[str, str | int | Position | Point | Size | None]] = {}
         monitors = _NSgetAllMonitorsDict()
         monKeys = list(monitors.keys())
         if relativePos == Position.PRIMARY or relativePos == (0, 0):
@@ -275,23 +273,23 @@ def setPosition(self, relativePos: Union[int, Position, Point, Tuple[int, int]],
         _arrangeMonitors(arrangement)
 
     @property
-    def box(self) -> Optional[Box]:
+    def box(self) -> Box | None:
         frame = self.screen.frame()
         res = Box(int(frame.origin.x), int(frame.origin.y), int(frame.size.width), int(frame.size.height))
         return res
 
     @property
-    def rect(self) -> Optional[Rect]:
+    def rect(self) -> Rect | None:
         frame = self.screen.frame()
         res = Rect(int(frame.origin.x), int(frame.origin.y),
                    int(frame.origin.x) + int(frame.size.width), int(frame.origin.y) + int(frame.size.height))
         return res
 
     @property
-    def scale(self) -> Optional[Tuple[float, float]]:
+    def scale(self) -> tuple[float, float] | None:
         return _scale(self.handle)
 
-    def setScale(self, scale: Tuple[float, float], applyGlobally: bool = True):
+    def setScale(self, scale: tuple[float, float], applyGlobally: bool = True):
         # https://www.eizoglobal.com/support/compatibility/dpi_scaling_settings_mac_os_x/
 
         if scale is not None and isinstance(scale, tuple) and scale[0] >= 100 and scale[1] >= 100:
@@ -346,20 +344,20 @@ def filterValue(itemIn):
                 CG.CGDisplaySetDisplayMode(self.handle, targetMode, None)
 
     @property
-    def dpi(self) -> Optional[Tuple[float, float]]:
+    def dpi(self) -> tuple[float, float] | None:
         desc = self.screen.deviceDescription()
         dpi = desc[Quartz.NSDeviceResolution].sizeValue()
         dpiX, dpiY = int(dpi.width), int(dpi.height)
         return dpiX, dpiY
 
     @property
-    def orientation(self) -> Optional[Union[int, Orientation]]:
+    def orientation(self) -> int | Orientation | None:
         orientation = int(Quartz.CGDisplayRotation(self.handle) / 90)
         if orientation in (Orientation.NORMAL, Orientation.INVERTED, Orientation.LEFT, Orientation.RIGHT):
             return Orientation(orientation)
         return None
 
-    def setOrientation(self, orientation: Optional[Union[int, Orientation]]):
+    def setOrientation(self, orientation: int | Orientation | None):
         if (self._useIOOrientation
                 and orientation and orientation in (Orientation.NORMAL, Orientation.INVERTED, Orientation.LEFT, Orientation.RIGHT)):
             if self._iokit is None:
@@ -388,17 +386,17 @@ def setOrientation(self, orientation: Optional[Union[int, Orientation]]):
                 self._useIOOrientation = False
 
     @property
-    def frequency(self) -> Optional[float]:
+    def frequency(self) -> float | None:
         freq = Quartz.CGDisplayModeGetRefreshRate(Quartz.CGDisplayCopyDisplayMode(self.handle))
         return freq
 
     @property
-    def colordepth(self) -> Optional[int]:
+    def colordepth(self) -> int | None:
         depth = Quartz.CGDisplayBitsPerPixel(self.handle)
         return depth
 
     @property
-    def brightness(self) -> Optional[int]:
+    def brightness(self) -> int | None:
         res = None
         ret = 1
         if self._useDS:
@@ -452,7 +450,7 @@ def brightness(self) -> Optional[int]:
             return int(res * 100)
         return None
 
-    def setBrightness(self, brightness: Optional[int]):
+    def setBrightness(self, brightness: int | None):
         # https://stackoverflow.com/questions/46885603/is-there-a-programmatic-way-to-check-if-brightness-is-at-max-or-min-value-on-osx
         if brightness is not None and 0 < brightness < 100:
             ret = 1
@@ -500,7 +498,7 @@ def setBrightness(self, brightness: Optional[int]):
                     self._useIOBrightness = False
 
     @property
-    def contrast(self) -> Optional[int]:
+    def contrast(self) -> int | None:
         # https://searchcode.com/file/2207916/pyobjc-framework-Quartz/PyObjCTest/test_cgdirectdisplay.py/
         contrast = None
         try:
@@ -512,7 +510,7 @@ def contrast(self) -> Optional[int]:
             pass
         return contrast
 
-    def setContrast(self, contrast: Optional[int]):
+    def setContrast(self, contrast: int | None):
         # https://searchcode.com/file/2207916/pyobjc-framework-Quartz/PyObjCTest/test_cgdirectdisplay.py/
         if contrast is not None and 0 <= contrast <= 100:
             ret, redMin, redMax, redGamma, greenMin, greenMax, greenGamma, blueMin, blueMax, blueGamma = (
@@ -540,14 +538,14 @@ def setContrast(self, contrast: Optional[int]):
                                                        )
 
     @property
-    def mode(self) -> Optional[DisplayMode]:
+    def mode(self) -> DisplayMode | None:
         mode = Quartz.CGDisplayCopyDisplayMode(self.handle)
         w = Quartz.CGDisplayModeGetWidth(mode)
         h = Quartz.CGDisplayModeGetHeight(mode)
         r = Quartz.CGDisplayModeGetRefreshRate(mode)
         return DisplayMode(w, h, r)
 
-    def setMode(self, mode: Optional[DisplayMode]):
+    def setMode(self, mode: DisplayMode | None):
         # https://stackoverflow.com/questions/10596489/programmatically-change-resolution-os-x
         # https://searchcode.com/file/2207916/pyobjc-framework-Quartz/PyObjCTest/test_cgdirectdisplay.py/
         if mode is not None:
@@ -565,8 +563,8 @@ def setMode(self, mode: Optional[DisplayMode]):
                     break
 
     @property
-    def defaultMode(self) -> Optional[DisplayMode]:
-        res: Optional[DisplayMode] = None
+    def defaultMode(self) -> DisplayMode | None:
+        res: DisplayMode | None = None
         modes = _CGgetAllModes(self.handle)
         for mode in modes:
             if bin(Quartz.CGDisplayModeGetIOFlags(mode))[-3] == '1':
@@ -585,8 +583,8 @@ def setDefaultMode(self):
                 break
 
     @property
-    def allModes(self) -> List[DisplayMode]:
-        modes: List[DisplayMode] = []
+    def allModes(self) -> list[DisplayMode]:
+        modes: list[DisplayMode] = []
         for mode in _CGgetAllModes(self.handle):
             w = Quartz.CGDisplayModeGetWidth(mode)
             h = Quartz.CGDisplayModeGetHeight(mode)
@@ -607,7 +605,7 @@ def setPrimary(self):
     def turnOn(self):
         cmd = "caffeinate -u -t 2"
         try:
-            _ = subprocess.run(cmd, text=True, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE, timeout=1)
+            _ = subprocess.run(cmd, text=True, shell=True, capture_output=True, timeout=1)
         except Exception:
             pass
 
@@ -615,19 +613,19 @@ def turnOff(self):
         self.suspend()
 
     @property
-    def isOn(self) -> Optional[bool]:
+    def isOn(self) -> bool | None:
         return bool(CG.CGDisplayIsActive(self.handle) == 1)
 
     def suspend(self):
         # Also injecting: Control–Shift–Media_Eject
         cmd = "pmset displaysleepnow"
         try:
-            _ = subprocess.run(cmd, text=True, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE, timeout=1)
+            _ = subprocess.run(cmd, text=True, shell=True, capture_output=True, timeout=1)
         except Exception:
             pass
 
     @property
-    def isSuspended(self) -> Optional[bool]:
+    def isSuspended(self) -> bool | None:
         return bool(CG.CGDisplayIsAsleep(self.handle) == 1)
 
     def attach(self):
@@ -638,11 +636,11 @@ def detach(self, permanent: bool = False):
         pass
 
     @property
-    def isAttached(self) -> Optional[bool]:
+    def isAttached(self) -> bool | None:
         return bool(CG.CGDisplayIsOnline(self.handle) == 1)
 
 
-def _getName(displayId: int, screen: Optional[AppKit.NSScreen] = None):
+def _getName(displayId: int, screen: AppKit.NSScreen | None = None):
     if not screen:
         for scr in AppKit.NSScreen.screens():
             desc = scr.deviceDescription()
@@ -650,7 +648,7 @@ def _getName(displayId: int, screen: Optional[AppKit.NSScreen] = None):
                 screen = scr
                 break
     try:
-        scrName = cast(AppKit.NSScreen, screen).localizedName() + "_" + str(displayId)
+        scrName = cast("AppKit.NSScreen", screen).localizedName() + "_" + str(displayId)
     except Exception:
         # In older macOS, screen doesn't have localizedName() method
         scrName = "Display" + "_" + str(displayId)
@@ -780,7 +778,7 @@ class _CFString(ctypes.Structure):
             kIOMasterPortDefault = ctypes.c_void_p.in_dll(iokit, "kIOMasterPortDefault")
 
             iterator = ctypes.c_void_p()
-            ret = iokit.IOServiceGetMatchingServices(
+            iokit.IOServiceGetMatchingServices(
                 kIOMasterPortDefault,
                 iokit.IOServiceMatching(b'IODisplayConnect'),
                 ctypes.byref(iterator)
diff --git a/src/pymonctl/_pymonctl_win.py b/src/pymonctl/_pymonctl_win.py
index 88f0713..4f1a873 100644
--- a/src/pymonctl/_pymonctl_win.py
+++ b/src/pymonctl/_pymonctl_win.py
@@ -1,5 +1,4 @@
 #!/usr/bin/python
-# -*- coding: utf-8 -*-
 from __future__ import annotations
 
 import sys
@@ -12,7 +11,6 @@
 
 import ctypes.wintypes
 import pywintypes
-from typing import Optional, List, Union, Tuple, cast
 import win32api
 import win32gui
 import win32con
@@ -100,7 +98,7 @@ def _getMonitorsCount() -> int:
     return len(win32api.EnumDisplayMonitors())
 
 
-def _findMonitor(x: int, y: int) -> List[Win32Monitor]:
+def _findMonitor(x: int, y: int) -> list[Win32Monitor]:
     # Watch this: started to fail when repeatedly and quickly invoking it in Python 3.10 (it was ok in 3.9)
     hMon = win32api.MonitorFromPoint((x, y), win32con.MONITOR_DEFAULTTONEAREST)
     if hMon and hasattr(hMon, "handle"):
@@ -115,7 +113,7 @@ def _getPrimary() -> Win32Monitor:
     return Win32Monitor()
 
 
-def _arrangeMonitors(arrangement: dict[str, dict[str, Optional[Union[str, int, Position, Point, Size]]]]):
+def _arrangeMonitors(arrangement: dict[str, dict[str, str | int | Position | Point | Size | None]]):
     # https://stackoverflow.com/questions/35814309/winapi-changedisplaysettingsex-does-not-work
     # https://stackoverflow.com/questions/195267/use-windows-api-from-c-sharp-to-set-primary-monitor
     monitors = _win32getAllMonitorsDict()
@@ -149,7 +147,7 @@ def _arrangeMonitors(arrangement: dict[str, dict[str, Optional[Union[str, int, P
 
         if monName != setAsPrimary:
 
-            relativePos: Union[Position, int, Point, Tuple[int, int]] = arrangement[monName]["relativePos"]
+            relativePos: Position | int | Point | tuple[int, int] = arrangement[monName]["relativePos"]
 
             if isinstance(relativePos, Position) or isinstance(relativePos, int):
 
@@ -194,7 +192,7 @@ def _getMousePos() -> Point:
 
 class Win32Monitor(BaseMonitor):
 
-    def __init__(self, handle: Optional[int] = None):
+    def __init__(self, handle: int | None = None) -> None:
         """
         Class to access all methods and functions to get info and manage monitors plugged to the system.
 
@@ -213,10 +211,10 @@ def __init__(self, handle: Optional[int] = None):
             self.name = monitorInfo.get("Device", "")
         else:
             raise ValueError
-        self._hasVCPSupport: Optional[bool] = None
-        self._hasVCPPowerSupport: Optional[bool] = None
-        self._sourceAdapterId: Optional[_LUID] = None
-        self._sourceId: Optional[int] = None
+        self._hasVCPSupport: bool | None = None
+        self._hasVCPPowerSupport: bool | None = None
+        self._sourceAdapterId: _LUID | None = None
+        self._sourceId: int | None = None
         self._isWindows11 = False
         try:
             self._isWindows11 = bool(int(platform.win32_ver()[1].rsplit(".", 1)[1]) >= 22000)
@@ -224,7 +222,7 @@ def __init__(self, handle: Optional[int] = None):
             self._isWindows11 = False
 
     @property
-    def size(self) -> Optional[Size]:
+    def size(self) -> Size | None:
         monitorInfo = _getMonitorInfo(self.handle)
         if monitorInfo:
             x, y, r, b = monitorInfo["Monitor"]
@@ -233,7 +231,7 @@ def size(self) -> Optional[Size]:
         return None
 
     @property
-    def workarea(self) -> Optional[Rect]:
+    def workarea(self) -> Rect | None:
         monitorInfo = _getMonitorInfo(self.handle)
         if monitorInfo:
             wx, wy, wr, wb = monitorInfo["Work"]
@@ -242,7 +240,7 @@ def workarea(self) -> Optional[Rect]:
         return None
 
     @property
-    def position(self) -> Optional[Point]:
+    def position(self) -> Point | None:
         monitorInfo = _getMonitorInfo(self.handle)
         if monitorInfo:
             x, y, r, b = monitorInfo["Monitor"]
@@ -250,10 +248,10 @@ def position(self) -> Optional[Point]:
                 return Point(x, y)
         return None
 
-    def setPosition(self, relativePos: Union[int, Position, Point, Tuple[int, int]], relativeTo: Optional[str]):
+    def setPosition(self, relativePos: int | Position | Point | tuple[int, int], relativeTo: str | None):
         # https://stackoverflow.com/questions/35814309/winapi-changedisplaysettingsex-does-not-work
         # https://stackoverflow.com/questions/195267/use-windows-api-from-c-sharp-to-set-primary-monitor
-        arrangement: dict[str, dict[str, Optional[Union[str, int, Position, Point, Size]]]] = {}
+        arrangement: dict[str, dict[str, str | int | Position | Point | Size | None]] = {}
         monitors = _win32getAllMonitorsDict()
         monKeys = list(monitors.keys())
         if relativePos == Position.PRIMARY or relativePos == (0, 0):
@@ -293,7 +291,7 @@ def setPosition(self, relativePos: Union[int, Position, Point, Tuple[int, int]],
         _arrangeMonitors(arrangement)
 
     @property
-    def box(self) -> Optional[Box]:
+    def box(self) -> Box | None:
         monitorInfo = _getMonitorInfo(self.handle)
         if monitorInfo:
             x, y, r, b = monitorInfo["Monitor"]
@@ -302,7 +300,7 @@ def box(self) -> Optional[Box]:
         return None
 
     @property
-    def rect(self) -> Optional[Rect]:
+    def rect(self) -> Rect | None:
         monitorInfo = _getMonitorInfo(self.handle)
         if monitorInfo:
             x, y, r, b = monitorInfo["Monitor"]
@@ -311,7 +309,7 @@ def rect(self) -> Optional[Rect]:
         return None
 
     @property
-    def scale(self) -> Optional[Tuple[float, float]]:
+    def scale(self) -> tuple[float, float] | None:
         pScale = ctypes.c_uint()
         ctypes.windll.shcore.GetScaleFactorForMonitor(self.handle, ctypes.byref(pScale))
         # import wmi
@@ -321,7 +319,7 @@ def scale(self) -> Optional[Tuple[float, float]]:
         #     print(item)
         return float(pScale.value), float(pScale.value)
 
-    def _getPaths(self) -> Tuple[Optional[_LUID], Optional[int]]:
+    def _getPaths(self) -> tuple[_LUID | None, int | None]:
 
         flags = _QDC_ONLY_ACTIVE_PATHS
         numPathArrayElements = ctypes.c_uint32()
@@ -359,7 +357,7 @@ def _getPaths(self) -> Tuple[Optional[_LUID], Optional[int]]:
                     i += 1
         return None, None
 
-    def setScale(self, scale: Optional[Tuple[float, float]], applyGlobally: bool = True):
+    def setScale(self, scale: tuple[float, float] | None, applyGlobally: bool = True):
 
         if scale is not None and isinstance(scale, tuple) and scale[0] >= 100 and scale[1] >= 100:
             # https://github.com/lihas/windows-DPI-scaling-sample/blob/master/DPIHelper/DpiHelper.cpp
@@ -409,14 +407,14 @@ def setScale(self, scale: Optional[Tuple[float, float]], applyGlobally: bool = T
                     ctypes.windll.user32.DisplayConfigSetDeviceInfo(ctypes.byref(setScaleData))
 
     @property
-    def dpi(self) -> Optional[Tuple[float, float]]:
+    def dpi(self) -> tuple[float, float] | None:
         dpiX = ctypes.c_uint()
         dpiY = ctypes.c_uint()
         ctypes.windll.shcore.GetDpiForMonitor(self.handle, 0, ctypes.byref(dpiX), ctypes.byref(dpiY))
         return dpiX.value, dpiY.value
 
     @property
-    def orientation(self) -> Optional[Union[int, Orientation]]:
+    def orientation(self) -> int | Orientation | None:
         # Settings content: http://timgolden.me.uk/pywin32-docs/PyDEVMODE.html
         settings = None
         try:
@@ -430,7 +428,7 @@ def orientation(self) -> Optional[Union[int, Orientation]]:
             return Orientation(settings.DisplayOrientation)
         return None
 
-    def setOrientation(self, orientation: Optional[Union[int, Orientation]]):
+    def setOrientation(self, orientation: int | Orientation | None):
         if orientation is not None and orientation in (Orientation.NORMAL, Orientation.INVERTED, Orientation.LEFT, Orientation.RIGHT):
             # In most cases an empty struct is required, but in this case we need to retrieve Display Settings first
             try:
@@ -449,7 +447,7 @@ def setOrientation(self, orientation: Optional[Union[int, Orientation]]):
             # win32api.ChangeDisplaySettingsEx()
 
     @property
-    def frequency(self) -> Optional[float]:
+    def frequency(self) -> float | None:
         settings = None
         try:
             settings = win32api.EnumDisplaySettings(self.name, win32con.ENUM_CURRENT_SETTINGS)
@@ -464,7 +462,7 @@ def frequency(self) -> Optional[float]:
     refreshRate = frequency
 
     @property
-    def colordepth(self) -> Optional[int]:
+    def colordepth(self) -> int | None:
         settings = None
         try:
             settings = win32api.EnumDisplaySettings(self.name, win32con.ENUM_CURRENT_SETTINGS)
@@ -478,7 +476,7 @@ def colordepth(self) -> Optional[int]:
         return None
 
     @property
-    def brightness(self) -> Optional[int]:
+    def brightness(self) -> int | None:
         minBright = ctypes.c_uint()
         currBright = ctypes.c_uint()
         maxBright = ctypes.c_uint()
@@ -491,7 +489,7 @@ def brightness(self) -> Optional[int]:
                 return currBright.value
         return None
 
-    def setBrightness(self, brightness: Optional[int]):
+    def setBrightness(self, brightness: int | None):
         if brightness is not None and 0 <= brightness <= 100:
             minBright = ctypes.c_uint()
             currBright = ctypes.c_uint()
@@ -508,7 +506,7 @@ def setBrightness(self, brightness: Optional[int]):
                 ctypes.windll.dxva2.DestroyPhysicalMonitor(hDevice)
 
     @property
-    def contrast(self) -> Optional[int]:
+    def contrast(self) -> int | None:
         minCont = ctypes.c_uint()
         currCont = ctypes.c_uint()
         maxCont = ctypes.c_uint()
@@ -521,7 +519,7 @@ def contrast(self) -> Optional[int]:
                 return currCont.value
         return None
 
-    def setContrast(self, contrast: Optional[int]):
+    def setContrast(self, contrast: int | None):
         if contrast is not None and 0 <= contrast <= 100:
             minCont = ctypes.c_uint()
             currCont = ctypes.c_uint()
@@ -538,7 +536,7 @@ def setContrast(self, contrast: Optional[int]):
                 ctypes.windll.dxva2.DestroyPhysicalMonitor(hDevice)
 
     @property
-    def mode(self) -> Optional[DisplayMode]:
+    def mode(self) -> DisplayMode | None:
         settings = None
         try:
             settings = win32api.EnumDisplaySettings(self.name, win32con.ENUM_CURRENT_SETTINGS)
@@ -551,7 +549,7 @@ def mode(self) -> Optional[DisplayMode]:
             return DisplayMode(settings.PelsWidth, settings.PelsHeight, settings.DisplayFrequency)
         return None
 
-    def setMode(self, mode: Optional[DisplayMode]):
+    def setMode(self, mode: DisplayMode | None):
         if mode is not None:
             # devmode = win32api.EnumDisplaySettings(self.name, win32con.ENUM_CURRENT_SETTINGS)
             devmode = pywintypes.DEVMODEType()
@@ -563,7 +561,7 @@ def setMode(self, mode: Optional[DisplayMode]):
             # win32api.ChangeDisplaySettingsEx()
 
     @property
-    def defaultMode(self) -> Optional[DisplayMode]:
+    def defaultMode(self) -> DisplayMode | None:
         settings = win32api.EnumDisplaySettings(self.name, win32con.ENUM_REGISTRY_SETTINGS)
         return DisplayMode(settings.PelsWidth, settings.PelsHeight, settings.DisplayFrequency)
 
@@ -574,7 +572,7 @@ def setDefaultMode(self):
 
     @property
     def allModes(self) -> list[DisplayMode]:
-        modes: List[DisplayMode] = []
+        modes: list[DisplayMode] = []
         i = 0
         while True:
             try:
@@ -658,8 +656,8 @@ def turnOff(self):
                                         2, win32con.SMTO_ABORTIFHUNG, 100)
 
     @property
-    def isOn(self) -> Optional[bool]:
-        ret: Optional[bool] = None
+    def isOn(self) -> bool | None:
+        ret: bool | None = None
         if self._hasVCPSupport is None:
             self._hasVCPSupport = _win32hasVCPSupport(self.handle)
             self._hasVCPPowerSupport = _win32hasVCPPowerSupport(self.handle)
@@ -705,8 +703,8 @@ def suspend(self):
                                         1, win32con.SMTO_ABORTIFHUNG, 100)
 
     @property
-    def isSuspended(self) -> Optional[bool]:
-        ret: Optional[bool] = None
+    def isSuspended(self) -> bool | None:
+        ret: bool | None = None
         if self._hasVCPSupport is None:
             self._hasVCPSupport = _win32hasVCPSupport(self.handle)
             self._hasVCPPowerSupport = _win32hasVCPPowerSupport(self.handle)
@@ -747,7 +745,7 @@ def detach(self, permanent: bool = False):
             _findNewHandles()
 
     @property
-    def isAttached(self) -> Optional[bool]:
+    def isAttached(self) -> bool | None:
         # Settings content: http://timgolden.me.uk/pywin32-docs/PyDEVMODE.html
         # This seems to return invalid values (2 instead of 3) in some cases (monitor 1 affected by monitor 3!?!?!?!)
         # dev = win32api.EnumDisplayDevices(self.name, 0, 0)
@@ -916,7 +914,7 @@ def _eventLoop(kill: threading.Event, interval: float):
 
     class NotificationWindow:
 
-        def __init__(self):
+        def __init__(self) -> None:
             hinst = win32api.GetModuleHandle(None)
             wndclass = win32gui.WNDCLASS()
             wndclass.hInstance = hinst  # type: ignore[misc]
diff --git a/src/pymonctl/_structs.py b/src/pymonctl/_structs.py
index 99fd77d..945d598 100644
--- a/src/pymonctl/_structs.py
+++ b/src/pymonctl/_structs.py
@@ -1,10 +1,9 @@
 #!/usr/bin/python
-# -*- coding: utf-8 -*-
 from __future__ import annotations
 
 import sys
 from enum import IntEnum
-from typing import NamedTuple, Tuple, TypedDict
+from typing import NamedTuple, TypedDict
 
 
 class Box(NamedTuple):
@@ -57,8 +56,8 @@ class ScreenValue(TypedDict):
     position: Point
     size: Size
     workarea: Rect
-    scale: Tuple[float, float]
-    dpi: Tuple[int, int]
+    scale: tuple[float, float]
+    dpi: tuple[int, int]
     orientation: int
     frequency: float
     colordepth: int
diff --git a/tests/test_pymonctl.py b/tests/test_pymonctl.py
index 43987fd..327794f 100644
--- a/tests/test_pymonctl.py
+++ b/tests/test_pymonctl.py
@@ -1,9 +1,8 @@
 #!/usr/bin/python
-# -*- coding: utf-8 -*-
 from __future__ import annotations
 
 import time
-from typing import Union, Optional, List, Tuple, cast
+from typing import cast
 
 import pymonctl as pmc
 
@@ -11,14 +10,14 @@
 _TIMELAP = 5
 
 
-def pluggedCB(names: List[str], info: dict[str, pmc.ScreenValue]):
+def pluggedCB(names: list[str], info: dict[str, pmc.ScreenValue]) -> None:
     print("MONITOR (UN)PLUGGED!!!")
     print(names)
     print(info)
     print()
 
 
-def changedCB(names: List[str], info: dict[str, pmc.ScreenValue]):
+def changedCB(names: list[str], info: dict[str, pmc.ScreenValue]) -> None:
     print("MONITOR CHANGED!!!")
     print(names)
     print(info)
@@ -26,23 +25,26 @@ def changedCB(names: List[str], info: dict[str, pmc.ScreenValue]):
 
 
 print("MONITORS COUNT:", pmc.getMonitorsCount())
-print("PRIMARY MONITOR:", pmc.getPrimary().name)
+try:
+    print("PRIMARY MONITOR:", pmc.getPrimary().name)
+except ValueError:
+    print("PRIMARY MONITOR: None")
 print()
 monDict = pmc.getAllMonitorsDict()
 for mon in monDict:
     print(monDict[mon])
 print()
 
-monitorsPlugged: List[pmc.Monitor] = pmc.getAllMonitors()
-initArrangement: List[Tuple[pmc.Monitor, pmc.ScreenValue]] = []
-initDict: dict[str, dict[str, Optional[Union[str, int, pmc.Position, pmc.Point, pmc.Size]]]] = {}
-setAsPrimary: Optional[pmc.Monitor] = None
+monitorsPlugged: list[pmc.Monitor] = pmc.getAllMonitors()
+initArrangement: list[tuple[pmc.Monitor, pmc.ScreenValue]] = []
+initDict: dict[str, dict[str, str | int | pmc.Position | pmc.Point | pmc.Size | None]] = {}
+setAsPrimary: pmc.Monitor | None = None
 try:
     initArrangement = pmc.saveSetup()
     print("INITIAL POSITIONS:", initArrangement)
 except Exception:
     for monitor in monitorsPlugged:
-        initDict[monitor.name] = {"relativePos": cast(pmc.Point, monitor.position)}
+        initDict[monitor.name] = {"relativePos": cast("pmc.Point", monitor.position)}
         if monitor.isPrimary:
             setAsPrimary = monitor
     print("INITIAL POSITIONS:", initDict)
@@ -231,7 +233,7 @@ def changedCB(names: List[str], info: dict[str, pmc.ScreenValue]):
         print()
 
     print("CHANGE ARRANGEMENT: MONITOR 2 AS PRIMARY, REST OF MONITORS AT LEFT_BOTTOM")
-    arrangement: dict[str, dict[str, Union[str, int, pmc.Position, pmc.Point, pmc.Size, None]]] = {
+    arrangement: dict[str, dict[str, str | int | pmc.Position | pmc.Point | pmc.Size | None]] = {
         str(mon2.name): {"relativePos": pmc.Position.PRIMARY, "relativeTo": ""}
     }
     relativeTo = mon2.name
diff --git a/uv.lock b/uv.lock
index 7d716dc..f20c6c0 100644
--- a/uv.lock
+++ b/uv.lock
@@ -797,6 +797,7 @@ dev = [
     { name = "myst-parser", version = "3.0.1", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version < '3.10'" },
     { name = "myst-parser", version = "4.0.1", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version == '3.10.*'" },
     { name = "myst-parser", version = "5.1.0", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version >= '3.11'" },
+    { name = "ruff" },
     { name = "types-python-xlib", version = "0.33.0.20250809", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version < '3.10'" },
     { name = "types-python-xlib", version = "0.33.0.20260518", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version >= '3.10'" },
     { name = "types-pywin32" },
@@ -820,6 +821,7 @@ dev = [
     { name = "ewmhlib" },
     { name = "mypy", specifier = ">=0.990,<2" },
     { name = "myst-parser" },
+    { name = "ruff", specifier = ">=0.15.16" },
     { name = "types-python-xlib", specifier = ">=0.32" },
     { name = "types-pywin32", specifier = "<312.0.0.20260609" },
 ]
@@ -8423,6 +8425,31 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/04/54/6f679c435d28e0a568d8e8a7c0a93a09010818634c3c3907fc98d8983770/roman_numerals-4.1.0-py3-none-any.whl", hash = "sha256:647ba99caddc2cc1e55a51e4360689115551bf4476d90e8162cf8c345fe233c7", size = 7676, upload-time = "2025-12-17T18:25:33.098Z" },
 ]
 
+[[package]]
+name = "ruff"
+version = "0.15.17"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/8c/a9/3abdf488f1bf3d24c699415e454ed554a6350d5d89ce183be1ee0a3361ac/ruff-0.15.17.tar.gz", hash = "sha256:2ec446937fd16c8c4de2674a209cc5af64d9c6f17d21fbf1151054fa0bcf5219", size = 4743346, upload-time = "2026-06-11T17:54:47.663Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/db/4d/e11259f5da07cb6afb2d074c31bf09da9671993f7329d4f15d2fdc458301/ruff-0.15.17-py3-none-linux_armv6l.whl", hash = "sha256:d9feddb927fc68bd295f5eebc587a7e42cfaf9b65f60ca4a2386febff575da8f", size = 10856677, upload-time = "2026-06-11T17:54:49.533Z" },
+    { url = "https://files.pythonhosted.org/packages/29/3e/772d679e1a0dc058e58875bd2c0cb713a0530877b4a76fee3c7966df0d49/ruff-0.15.17-py3-none-macosx_10_12_x86_64.whl", hash = "sha256:25805a226d741c47d274a35ad5c10a7dde175fcddfa511d7cf3da0a21eb3eab7", size = 11223443, upload-time = "2026-06-11T17:55:00.573Z" },
+    { url = "https://files.pythonhosted.org/packages/68/58/bd41f7688b2fd5623012605130ed70e60aa7f2244baa3d5066bdd61530c8/ruff-0.15.17-py3-none-macosx_11_0_arm64.whl", hash = "sha256:f6ad73b14c2d18a3bf8ad7cb6974294d7f613a7898604826058e6ac64918ef4d", size = 10566458, upload-time = "2026-06-11T17:55:07.52Z" },
+    { url = "https://files.pythonhosted.org/packages/d8/5b/733371013fcf1ec339e477ece6ab42bfe10bdd9bba8ee88a9516aa56bfc0/ruff-0.15.17-py3-none-manylinux_2_17_aarch64.manylinux2014_aarch64.whl", hash = "sha256:6ba0c1e4f95bcb3869d0d30cbd5917071ef2e28665abfec970cdab0492c713ed", size = 10914483, upload-time = "2026-06-11T17:55:05.501Z" },
+    { url = "https://files.pythonhosted.org/packages/bd/cc/6f24251cc0252f7239391ccb85833f320efad14ebe5b443943f37ced6332/ruff-0.15.17-py3-none-manylinux_2_17_armv7l.manylinux2014_armv7l.whl", hash = "sha256:81647960f10bff57d2e51cadd0c3950fe598400c852863a038720ef5b8cca91e", size = 10647497, upload-time = "2026-06-11T17:54:57.733Z" },
+    { url = "https://files.pythonhosted.org/packages/68/dd/0d10c17ce1a1624d6fc3156309c3f834fdb5dfaad026ec90c85684f3990e/ruff-0.15.17-py3-none-manylinux_2_17_i686.manylinux2014_i686.whl", hash = "sha256:0e01a84ddbc8c16c23055ba3924476850f1bbc1917cebbb9376665a63e74260d", size = 11416967, upload-time = "2026-06-11T17:54:51.461Z" },
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+]
+
 [[package]]
 name = "six"
 version = "1.17.0"