diff --git a/.github/pages/make_switcher.py b/.github/pages/make_switcher.py
index 2b81e7696..6d90f4905 100755
--- a/.github/pages/make_switcher.py
+++ b/.github/pages/make_switcher.py
@@ -3,7 +3,6 @@
 from argparse import ArgumentParser
 from pathlib import Path
 from subprocess import CalledProcessError, check_output
-from typing import Optional
 
 
 def report_output(stdout: bytes, label: str) -> list[str]:
@@ -24,7 +23,7 @@ def get_sorted_tags_list() -> list[str]:
     return report_output(stdout, "Tags list")
 
 
-def get_versions(ref: str, add: Optional[str]) -> list[str]:
+def get_versions(ref: str, add: str | None) -> list[str]:
     """Generate the file containing the list of all GitHub Pages builds."""
     # Get the directories (i.e. builds) from the GitHub Pages branch
     try:
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 27769757f..f45e2aaad 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -21,7 +21,7 @@ jobs:
     strategy:
       matrix:
         runs-on: ["ubuntu-latest"] # can add windows-latest, macos-latest
-        python-version: ["3.9", "3.10", "3.11"]
+        python-version: ["3.10", "3.11"]
         include:
           # Include one that runs in the dev environment
           - runs-on: "ubuntu-latest"
diff --git a/pyproject.toml b/pyproject.toml
index 7681cb933..cb0bb3987 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -7,7 +7,6 @@ name = "blueapi"
 classifiers = [
     "Development Status :: 3 - Alpha",
     "License :: OSI Approved :: Apache Software License",
-    "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
 ]
@@ -32,7 +31,7 @@ dependencies = [
 dynamic = ["version"]
 license.file = "LICENSE"
 readme = "README.md"
-requires-python = ">=3.9"
+requires-python = ">=3.10"
 
 [project.optional-dependencies]
 dev = [
diff --git a/src/blueapi/cli/amq.py b/src/blueapi/cli/amq.py
index b9b6c0b3c..face01b4b 100644
--- a/src/blueapi/cli/amq.py
+++ b/src/blueapi/cli/amq.py
@@ -1,5 +1,5 @@
 import threading
-from typing import Callable, Optional, Union
+from collections.abc import Callable
 
 from bluesky.callbacks.best_effort import BestEffortCallback
 
@@ -15,13 +15,13 @@ def __init__(self, message: str) -> None:
         super().__init__(message)
 
 
-_Event = Union[WorkerEvent, ProgressEvent, DataEvent]
+_Event = WorkerEvent | ProgressEvent | DataEvent
 
 
 class AmqClient:
     app: MessagingTemplate
     complete: threading.Event
-    timed_out: Optional[bool]
+    timed_out: bool | None
 
     def __init__(self, app: MessagingTemplate) -> None:
         self.app = app
@@ -37,7 +37,7 @@ def __exit__(self, exc_type, exc_value, exc_traceback) -> None:
     def subscribe_to_topics(
         self,
         correlation_id: str,
-        on_event: Optional[Callable[[WorkerEvent], None]] = None,
+        on_event: Callable[[WorkerEvent], None] | None = None,
     ) -> None:
         """Run callbacks on events/progress events with a given correlation id."""
 
@@ -70,7 +70,7 @@ def subscribe_to_all_events(
             on_event,
         )
 
-    def wait_for_complete(self, timeout: Optional[float] = None) -> None:
+    def wait_for_complete(self, timeout: float | None = None) -> None:
         self.timed_out = not self.complete.wait(timeout=timeout)
 
         self.complete.clear()
diff --git a/src/blueapi/cli/cli.py b/src/blueapi/cli/cli.py
index ab2f6549e..5bad55768 100644
--- a/src/blueapi/cli/cli.py
+++ b/src/blueapi/cli/cli.py
@@ -4,7 +4,6 @@
 from functools import wraps
 from pathlib import Path
 from pprint import pprint
-from typing import Optional, Union
 
 import click
 from requests.exceptions import ConnectionError
@@ -40,7 +39,7 @@
     "-c", "--config", type=Path, help="Path to configuration YAML file", multiple=True
 )
 @click.pass_context
-def main(ctx: click.Context, config: Union[Optional[Path], tuple[Path, ...]]) -> None:
+def main(ctx: click.Context, config: Path | None | tuple[Path, ...]) -> None:
     # if no command is supplied, run with the options passed
 
     config_loader = ConfigLoader(ApplicationConfig)
@@ -71,7 +70,7 @@ def main(ctx: click.Context, config: Union[Optional[Path], tuple[Path, ...]]) ->
     is_flag=True,
     help="[Development only] update the schema in the documentation",
 )
-def schema(output: Optional[Path] = None, update: bool = False) -> None:
+def schema(output: Path | None = None, update: bool = False) -> None:
     """Generate the schema for the REST API"""
     schema = generate_schema()
 
@@ -167,7 +166,7 @@ def is_allowed(event: Union[WorkerEvent, ProgressEvent, DataEvent]) -> bool:
 
     def on_event(
         context: MessageContext,
-        event: Union[WorkerEvent, ProgressEvent, DataEvent],
+        event: WorkerEvent | ProgressEvent | DataEvent,
     ) -> None:
         if is_allowed(event):
             converted = json.dumps(event.dict(), indent=2)
@@ -195,7 +194,7 @@ def on_event(
 @check_connection
 @click.pass_obj
 def run_plan(
-    obj: dict, name: str, parameters: Optional[str], timeout: Optional[float]
+    obj: dict, name: str, parameters: str | None, timeout: float | None
 ) -> None:
     """Run a plan with parameters"""
     config: ApplicationConfig = obj["config"]
@@ -265,7 +264,7 @@ def resume(obj: dict) -> None:
 @check_connection
 @click.argument("reason", type=str, required=False)
 @click.pass_obj
-def abort(obj: dict, reason: Optional[str] = None) -> None:
+def abort(obj: dict, reason: str | None = None) -> None:
     """
     Abort the execution of the current task, marking any ongoing runs as failed,
     with optional reason
diff --git a/src/blueapi/cli/rest.py b/src/blueapi/cli/rest.py
index 111986d2e..5e363faee 100644
--- a/src/blueapi/cli/rest.py
+++ b/src/blueapi/cli/rest.py
@@ -1,5 +1,5 @@
-from collections.abc import Mapping
-from typing import Any, Callable, Literal, Optional, TypeVar
+from collections.abc import Callable, Mapping
+from typing import Any, Literal, TypeVar
 
 import requests
 from pydantic import parse_obj_as
@@ -27,7 +27,7 @@ def _is_exception(response: requests.Response) -> bool:
 class BlueapiRestClient:
     _config: RestConfig
 
-    def __init__(self, config: Optional[RestConfig] = None) -> None:
+    def __init__(self, config: RestConfig | None = None) -> None:
         self._config = config or RestConfig()
 
     def get_plans(self) -> PlanResponse:
@@ -48,7 +48,7 @@ def get_state(self) -> WorkerState:
     def set_state(
         self,
         state: Literal[WorkerState.RUNNING, WorkerState.PAUSED],
-        defer: Optional[bool] = False,
+        defer: bool | None = False,
     ):
         return self._request_and_deserialize(
             "/worker/state",
@@ -87,7 +87,7 @@ def update_worker_task(self, task: WorkerTask) -> WorkerTask:
     def cancel_current_task(
         self,
         state: Literal[WorkerState.ABORTING, WorkerState.STOPPING],
-        reason: Optional[str] = None,
+        reason: str | None = None,
     ):
         return self._request_and_deserialize(
             "/worker/state",
@@ -100,7 +100,7 @@ def _request_and_deserialize(
         self,
         suffix: str,
         target_type: type[T],
-        data: Optional[Mapping[str, Any]] = None,
+        data: Mapping[str, Any] | None = None,
         method="GET",
         raise_if: Callable[[requests.Response], bool] = _is_exception,
     ) -> T:
diff --git a/src/blueapi/cli/updates.py b/src/blueapi/cli/updates.py
index 530abfa2e..7b7d73dd0 100644
--- a/src/blueapi/cli/updates.py
+++ b/src/blueapi/cli/updates.py
@@ -1,6 +1,5 @@
 import itertools
 from collections.abc import Mapping
-from typing import Optional, Union
 
 from tqdm import tqdm
 
@@ -44,13 +43,13 @@ def _update(self, name: str, view: StatusView) -> None:
 
 
 class CliEventRenderer:
-    _task_id: Optional[str]
+    _task_id: str | None
     _pbar_renderer: ProgressBarRenderer
 
     def __init__(
         self,
-        task_id: Optional[str] = None,
-        pbar_renderer: Optional[ProgressBarRenderer] = None,
+        task_id: str | None = None,
+        pbar_renderer: ProgressBarRenderer | None = None,
     ) -> None:
         self._task_id = task_id
         if pbar_renderer is None:
@@ -65,7 +64,7 @@ def on_worker_event(self, event: WorkerEvent) -> None:
         if self._relates_to_task(event):
             print(str(event.state))
 
-    def _relates_to_task(self, event: Union[WorkerEvent, ProgressEvent]) -> bool:
+    def _relates_to_task(self, event: WorkerEvent | ProgressEvent) -> bool:
         if self._task_id is None:
             return True
         elif isinstance(event, WorkerEvent):
diff --git a/src/blueapi/config.py b/src/blueapi/config.py
index f109bb36a..88180cb5e 100644
--- a/src/blueapi/config.py
+++ b/src/blueapi/config.py
@@ -2,7 +2,7 @@
 from collections.abc import Mapping
 from enum import Enum
 from pathlib import Path
-from typing import Any, Generic, Literal, Optional, TypeVar, Union
+from typing import Any, Generic, Literal, TypeVar
 
 import yaml
 from pydantic import BaseModel, Field, ValidationError, parse_obj_as, validator
@@ -20,7 +20,7 @@ class SourceKind(str, Enum):
 
 class Source(BaseModel):
     kind: SourceKind
-    module: Union[Path, str]
+    module: Path | str
 
 
 class BasicAuthentication(BaseModel):
@@ -48,11 +48,11 @@ class StompConfig(BaseModel):
 
     host: str = "localhost"
     port: int = 61613
-    auth: Optional[BasicAuthentication] = None
+    auth: BasicAuthentication | None = None
 
 
 class DataWritingConfig(BlueapiBaseModel):
-    visit_service_url: Optional[str] = None  # e.g. "http://localhost:8088/api"
+    visit_service_url: str | None = None  # e.g. "http://localhost:8088/api"
     visit_directory: Path = Path("/tmp/0-0")
     group_name: str = "example"
 
diff --git a/src/blueapi/core/bluesky_types.py b/src/blueapi/core/bluesky_types.py
index 6514da056..ce5fd66d3 100644
--- a/src/blueapi/core/bluesky_types.py
+++ b/src/blueapi/core/bluesky_types.py
@@ -1,11 +1,8 @@
 import inspect
-from collections.abc import Mapping
+from collections.abc import Callable, Mapping
 from typing import (
     Any,
-    Callable,
-    Optional,
     Protocol,
-    Union,
     get_type_hints,
     runtime_checkable,
 )
@@ -37,23 +34,23 @@
 
 #: An object that encapsulates the device to do useful things to produce
 # data (e.g. move and read)
-Device = Union[
-    Checkable,
-    Flyable,
-    HasHints,
-    HasName,
-    HasParent,
-    Movable,
-    Pausable,
-    Readable,
-    Stageable,
-    Stoppable,
-    Subscribable,
-    WritesExternalAssets,
-    Configurable,
-    Triggerable,
-    AsyncDevice,
-]
+Device = (
+    Checkable
+    | Flyable
+    | HasHints
+    | HasName
+    | HasParent
+    | Movable
+    | Pausable
+    | Readable
+    | Stageable
+    | Stoppable
+    | Subscribable
+    | WritesExternalAssets
+    | Configurable
+    | Triggerable
+    | AsyncDevice
+)
 
 #: Protocols defining interface to hardware
 BLUESKY_PROTOCOLS = list(Device.__args__)  # type: ignore
@@ -90,7 +87,7 @@ class Plan(BlueapiBaseModel):
     """
 
     name: str = Field(description="Referenceable name of the plan")
-    description: Optional[str] = Field(
+    description: str | None = Field(
         description="Description/docstring of the plan", default=None
     )
     model: type[BaseModel] = Field(
diff --git a/src/blueapi/core/context.py b/src/blueapi/core/context.py
index a4ac20d7e..07dc90b10 100644
--- a/src/blueapi/core/context.py
+++ b/src/blueapi/core/context.py
@@ -1,17 +1,14 @@
 import functools
 import logging
-from collections.abc import Sequence
+from collections.abc import Callable, Sequence
 from dataclasses import dataclass, field
 from importlib import import_module
 from inspect import Parameter, signature
 from types import ModuleType
 from typing import (
     Any,
-    Callable,
     Generic,
-    Optional,
     TypeVar,
-    Union,
     get_args,
     get_origin,
     get_type_hints,
@@ -71,7 +68,7 @@ def wrap(self, plan: MsgGenerator) -> MsgGenerator:
         )
         yield from wrapped_plan
 
-    def find_device(self, addr: Union[str, list[str]]) -> Optional[Device]:
+    def find_device(self, addr: str | list[str]) -> Device | None:
         """
         Find a device in this context, allows for recursive search.
 
@@ -168,7 +165,7 @@ def my_plan(a: int, b: str):
         self.plan_functions[plan.__name__] = plan
         return plan
 
-    def device(self, device: Device, name: Optional[str] = None) -> None:
+    def device(self, device: Device, name: str | None = None) -> None:
         """
         Register an device in the context. The device needs to be registered with a
         name. If the device is Readable, Movable or Flyable it has a `name`
@@ -223,7 +220,7 @@ def valid(cls, value):
 
                 @classmethod
                 def __modify_schema__(
-                    cls, field_schema: dict[str, Any], field: Optional[ModelField]
+                    cls, field_schema: dict[str, Any], field: ModelField | None
                 ):
                     if field:
                         field_schema.update({field.name: repr(target)})
diff --git a/src/blueapi/core/device_lookup.py b/src/blueapi/core/device_lookup.py
index 28e616ede..1bace1676 100644
--- a/src/blueapi/core/device_lookup.py
+++ b/src/blueapi/core/device_lookup.py
@@ -1,4 +1,4 @@
-from typing import Any, Optional, TypeVar
+from typing import Any, TypeVar
 
 from .bluesky_types import Device, is_bluesky_compatible_device
 
@@ -6,7 +6,7 @@
 D = TypeVar("D", bound=Device)
 
 
-def find_component(obj: Any, addr: list[str]) -> Optional[D]:
+def find_component(obj: Any, addr: list[str]) -> D | None:
     """
     Best effort function to locate a child device, either in a dictionary of
     devices or a device with child attributes.
diff --git a/src/blueapi/core/event.py b/src/blueapi/core/event.py
index dbda0694d..fff9c833d 100644
--- a/src/blueapi/core/event.py
+++ b/src/blueapi/core/event.py
@@ -1,6 +1,7 @@
 import itertools
 from abc import ABC, abstractmethod
-from typing import Callable, Generic, Optional, TypeVar
+from collections.abc import Callable
+from typing import Generic, TypeVar
 
 #: Event type
 E = TypeVar("E")
@@ -15,7 +16,7 @@ class EventStream(ABC, Generic[E, S]):
     """
 
     @abstractmethod
-    def subscribe(self, __callback: Callable[[E, Optional[str]], None]) -> S:
+    def subscribe(self, __callback: Callable[[E, str | None], None]) -> S:
         """
         Subscribe to new events with a callback
 
@@ -47,14 +48,14 @@ class EventPublisher(EventStream[E, int]):
     Simple Observable that can be fed values to publish
     """
 
-    _subscriptions: dict[int, Callable[[E, Optional[str]], None]]
+    _subscriptions: dict[int, Callable[[E, str | None], None]]
     _count: itertools.count
 
     def __init__(self) -> None:
         self._subscriptions = {}
         self._count = itertools.count()
 
-    def subscribe(self, callback: Callable[[E, Optional[str]], None]) -> int:
+    def subscribe(self, callback: Callable[[E, str | None], None]) -> int:
         sub_id = next(self._count)
         self._subscriptions[sub_id] = callback
         return sub_id
@@ -65,7 +66,7 @@ def unsubscribe(self, subscription: int) -> None:
     def unsubscribe_all(self) -> None:
         self._subscriptions = {}
 
-    def publish(self, event: E, correlation_id: Optional[str] = None) -> None:
+    def publish(self, event: E, correlation_id: str | None = None) -> None:
         """
         Publish a new event to all subscribers
 
diff --git a/src/blueapi/data_management/visit_directory_provider.py b/src/blueapi/data_management/visit_directory_provider.py
index 9b27e9d9c..bc05040b7 100644
--- a/src/blueapi/data_management/visit_directory_provider.py
+++ b/src/blueapi/data_management/visit_directory_provider.py
@@ -1,7 +1,6 @@
 import logging
 from abc import ABC, abstractmethod
 from pathlib import Path
-from typing import Optional
 
 from aiohttp import ClientSession
 from ophyd_async.core import DirectoryInfo, DirectoryProvider
@@ -75,8 +74,8 @@ class VisitDirectoryProvider(DirectoryProvider):
     _data_directory: Path
 
     _client: VisitServiceClientBase
-    _current_collection: Optional[DirectoryInfo]
-    _session: Optional[ClientSession]
+    _current_collection: DirectoryInfo | None
+    _session: ClientSession | None
 
     def __init__(
         self,
diff --git a/src/blueapi/messaging/base.py b/src/blueapi/messaging/base.py
index bd517a6a2..6c350639a 100644
--- a/src/blueapi/messaging/base.py
+++ b/src/blueapi/messaging/base.py
@@ -1,6 +1,7 @@
 from abc import ABC, abstractmethod
+from collections.abc import Callable
 from concurrent.futures import Future
-from typing import Any, Callable, Optional
+from typing import Any
 
 from .context import MessageContext
 
@@ -87,7 +88,7 @@ def send_and_receive(
         destination: str,
         obj: Any,
         reply_type: type = str,
-        correlation_id: Optional[str] = None,
+        correlation_id: str | None = None,
     ) -> Future:
         """
         Send a message expecting a single reply.
@@ -118,8 +119,8 @@ def send(
         self,
         destination: str,
         obj: Any,
-        on_reply: Optional[MessageListener] = None,
-        correlation_id: Optional[str] = None,
+        on_reply: MessageListener | None = None,
+        correlation_id: str | None = None,
     ) -> None:
         """
         Send a message to a destination
diff --git a/src/blueapi/messaging/context.py b/src/blueapi/messaging/context.py
index be79a3958..d202b700e 100644
--- a/src/blueapi/messaging/context.py
+++ b/src/blueapi/messaging/context.py
@@ -1,5 +1,4 @@
 from dataclasses import dataclass
-from typing import Optional
 
 
 @dataclass
@@ -9,5 +8,5 @@ class MessageContext:
     """
 
     destination: str
-    reply_destination: Optional[str]
-    correlation_id: Optional[str]
+    reply_destination: str | None
+    correlation_id: str | None
diff --git a/src/blueapi/messaging/stomptemplate.py b/src/blueapi/messaging/stomptemplate.py
index e56c72435..bf107c36b 100644
--- a/src/blueapi/messaging/stomptemplate.py
+++ b/src/blueapi/messaging/stomptemplate.py
@@ -3,9 +3,10 @@
 import logging
 import time
 import uuid
+from collections.abc import Callable
 from dataclasses import dataclass
 from threading import Event
-from typing import Any, Callable, Optional
+from typing import Any
 
 import stomp
 from pydantic import parse_obj_as
@@ -84,8 +85,8 @@ class StompMessagingTemplate(MessagingTemplate):
     def __init__(
         self,
         conn: stomp.Connection,
-        reconnect_policy: Optional[StompReconnectPolicy] = None,
-        authentication: Optional[BasicAuthentication] = None,
+        reconnect_policy: StompReconnectPolicy | None = None,
+        authentication: BasicAuthentication | None = None,
     ) -> None:
         self._conn = conn
         self._reconnect_policy = reconnect_policy or StompReconnectPolicy()
@@ -117,8 +118,8 @@ def send(
         self,
         destination: str,
         obj: Any,
-        on_reply: Optional[MessageListener] = None,
-        correlation_id: Optional[str] = None,
+        on_reply: MessageListener | None = None,
+        correlation_id: str | None = None,
     ) -> None:
         self._send_str(
             destination, json.dumps(serialize(obj)), on_reply, correlation_id
@@ -128,8 +129,8 @@ def _send_str(
         self,
         destination: str,
         message: str,
-        on_reply: Optional[MessageListener] = None,
-        correlation_id: Optional[str] = None,
+        on_reply: MessageListener | None = None,
+        correlation_id: str | None = None,
     ) -> None:
         LOGGER.info(f"SENDING {message} to {destination}")
 
@@ -193,7 +194,7 @@ def finished_connecting(_: Frame):
 
         self._ensure_subscribed()
 
-    def _ensure_subscribed(self, sub_ids: Optional[list[str]] = None) -> None:
+    def _ensure_subscribed(self, sub_ids: list[str] | None = None) -> None:
         # We must defer subscription until after connection, because stomp literally
         # sends a SUB to the broker. But it still nice to be able to call subscribe
         # on template before it connects, then just run the subscribes after connection.
diff --git a/src/blueapi/service/handler.py b/src/blueapi/service/handler.py
index be2016262..f38dcf434 100644
--- a/src/blueapi/service/handler.py
+++ b/src/blueapi/service/handler.py
@@ -1,6 +1,5 @@
 import logging
 from collections.abc import Mapping
-from typing import Optional
 
 from blueapi.config import ApplicationConfig
 from blueapi.core import BlueskyContext
@@ -33,10 +32,10 @@ class Handler(BlueskyHandler):
 
     def __init__(
         self,
-        config: Optional[ApplicationConfig] = None,
-        context: Optional[BlueskyContext] = None,
-        messaging_template: Optional[MessagingTemplate] = None,
-        worker: Optional[Worker] = None,
+        config: ApplicationConfig | None = None,
+        context: BlueskyContext | None = None,
+        messaging_template: MessagingTemplate | None = None,
+        worker: Worker | None = None,
     ) -> None:
         self._config = config or ApplicationConfig()
         self._context = context or BlueskyContext()
@@ -115,27 +114,27 @@ def begin_task(self, task: WorkerTask) -> WorkerTask:
         return task
 
     @property
-    def active_task(self) -> Optional[TrackableTask]:
+    def active_task(self) -> TrackableTask | None:
         return self._worker.get_active_task()
 
     @property
     def state(self) -> WorkerState:
         return self._worker.state
 
-    def pause_worker(self, defer: Optional[bool]) -> None:
+    def pause_worker(self, defer: bool | None) -> None:
         self._worker.pause(defer)
 
     def resume_worker(self) -> None:
         self._worker.resume()
 
-    def cancel_active_task(self, failure: bool, reason: Optional[str]):
+    def cancel_active_task(self, failure: bool, reason: str | None):
         self._worker.cancel_active_task(failure, reason)
 
     @property
     def tasks(self) -> list[TrackableTask]:
         return self._worker.get_tasks()
 
-    def get_task_by_id(self, task_id: str) -> Optional[TrackableTask]:
+    def get_task_by_id(self, task_id: str) -> TrackableTask | None:
         return self._worker.get_task_by_id(task_id)
 
     @property
@@ -143,11 +142,11 @@ def initialized(self) -> bool:
         return self._initialized
 
 
-HANDLER: Optional[Handler] = None
+HANDLER: Handler | None = None
 
 
 def setup_handler(
-    config: Optional[ApplicationConfig] = None,
+    config: ApplicationConfig | None = None,
 ) -> None:
     global HANDLER
 
diff --git a/src/blueapi/service/handler_base.py b/src/blueapi/service/handler_base.py
index 36e8090e9..0671ebad8 100644
--- a/src/blueapi/service/handler_base.py
+++ b/src/blueapi/service/handler_base.py
@@ -1,5 +1,4 @@
 from abc import ABC, abstractmethod
-from typing import Optional
 
 from blueapi.service.model import DeviceModel, PlanModel, WorkerTask
 from blueapi.worker.event import WorkerState
@@ -52,7 +51,7 @@ def begin_task(self, task: WorkerTask) -> WorkerTask:
 
     @property
     @abstractmethod
-    def active_task(self) -> Optional[TrackableTask]:
+    def active_task(self) -> TrackableTask | None:
         """Task the worker is currently running"""
 
     @property
@@ -61,7 +60,7 @@ def state(self) -> WorkerState:
         """State of the worker"""
 
     @abstractmethod
-    def pause_worker(self, defer: Optional[bool]) -> None:
+    def pause_worker(self, defer: bool | None) -> None:
         """Command the worker to pause"""
 
     @abstractmethod
@@ -69,7 +68,7 @@ def resume_worker(self) -> None:
         """Command the worker to resume"""
 
     @abstractmethod
-    def cancel_active_task(self, failure: bool, reason: Optional[str]) -> None:
+    def cancel_active_task(self, failure: bool, reason: str | None) -> None:
         """Remove the currently active task from the worker if there is one
         Returns the task_id of the active task"""
 
@@ -80,7 +79,7 @@ def tasks(self) -> list[TrackableTask]:
         any one of which can be triggered with begin_task"""
 
     @abstractmethod
-    def get_task_by_id(self, task_id: str) -> Optional[TrackableTask]:
+    def get_task_by_id(self, task_id: str) -> TrackableTask | None:
         """Returns a task matching the task ID supplied,
         if the worker knows of it"""
 
diff --git a/src/blueapi/service/main.py b/src/blueapi/service/main.py
index e41c992d8..9c0551cd7 100644
--- a/src/blueapi/service/main.py
+++ b/src/blueapi/service/main.py
@@ -1,5 +1,4 @@
 from contextlib import asynccontextmanager
-from typing import Optional
 
 from fastapi import (
     BackgroundTasks,
@@ -33,7 +32,7 @@
 
 REST_API_VERSION = "0.0.5"
 
-HANDLER: Optional[BlueskyHandler] = None
+HANDLER: BlueskyHandler | None = None
 
 
 def get_handler() -> BlueskyHandler:
@@ -42,7 +41,7 @@ def get_handler() -> BlueskyHandler:
     return HANDLER
 
 
-def setup_handler(config: Optional[ApplicationConfig] = None):
+def setup_handler(config: ApplicationConfig | None = None):
     global HANDLER
     handler = SubprocessHandler(config)
     handler.start()
diff --git a/src/blueapi/service/model.py b/src/blueapi/service/model.py
index 625ecc1e4..f8c42b33b 100644
--- a/src/blueapi/service/model.py
+++ b/src/blueapi/service/model.py
@@ -1,5 +1,5 @@
 from collections.abc import Iterable
-from typing import Any, Optional
+from typing import Any
 
 from bluesky.protocols import HasName
 from pydantic import Field
@@ -55,10 +55,8 @@ class PlanModel(BlueapiBaseModel):
     """
 
     name: str = Field(description="Name of the plan")
-    description: Optional[str] = Field(
-        description="Docstring of the plan", default=None
-    )
-    parameter_schema: Optional[dict[str, Any]] = Field(
+    description: str | None = Field(description="Docstring of the plan", default=None)
+    parameter_schema: dict[str, Any] | None = Field(
         description="Schema of the plan's parameters",
         alias="schema",
         default_factory=dict,
@@ -102,7 +100,7 @@ class WorkerTask(BlueapiBaseModel):
     Worker's active task ID, can be None
     """
 
-    task_id: Optional[str] = Field(
+    task_id: str | None = Field(
         description="The ID of the current task, None if the worker is idle"
     )
 
@@ -121,11 +119,11 @@ class StateChangeRequest(BlueapiBaseModel):
     """
 
     new_state: WorkerState = Field()
-    defer: Optional[bool] = Field(
+    defer: bool | None = Field(
         description="Should worker defer Pausing until the next checkpoint",
         default=False,
     )
-    reason: Optional[str] = Field(
+    reason: str | None = Field(
         description="The reason for the current run to be aborted",
         default=None,
     )
diff --git a/src/blueapi/service/subprocess_handler.py b/src/blueapi/service/subprocess_handler.py
index 13fc127b0..32c3d729a 100644
--- a/src/blueapi/service/subprocess_handler.py
+++ b/src/blueapi/service/subprocess_handler.py
@@ -1,9 +1,8 @@
 import logging
 import signal
-from collections.abc import Iterable
+from collections.abc import Callable, Iterable
 from multiprocessing import Pool, set_start_method
 from multiprocessing.pool import Pool as PoolClass
-from typing import Callable, Optional
 
 from blueapi.config import ApplicationConfig
 from blueapi.service.handler import get_handler, setup_handler, teardown_handler
@@ -24,12 +23,12 @@ def _init_worker():
 
 class SubprocessHandler(BlueskyHandler):
     _config: ApplicationConfig
-    _subprocess: Optional[PoolClass]
+    _subprocess: PoolClass | None
     _initialized: bool = False
 
     def __init__(
         self,
-        config: Optional[ApplicationConfig] = None,
+        config: ApplicationConfig | None = None,
     ) -> None:
         self._config = config or ApplicationConfig()
         self._subprocess = None
@@ -56,9 +55,7 @@ def reload_context(self):
         self.start()
         LOGGER.info("Context reloaded")
 
-    def _run_in_subprocess(
-        self, function: Callable, arguments: Optional[Iterable] = None
-    ):
+    def _run_in_subprocess(self, function: Callable, arguments: Iterable | None = None):
         if arguments is None:
             arguments = []
         if self._subprocess is None:
@@ -89,27 +86,27 @@ def begin_task(self, task: WorkerTask) -> WorkerTask:
         return self._run_in_subprocess(begin_task, [task])
 
     @property
-    def active_task(self) -> Optional[TrackableTask]:
+    def active_task(self) -> TrackableTask | None:
         return self._run_in_subprocess(active_task)
 
     @property
     def state(self) -> WorkerState:
         return self._run_in_subprocess(state)
 
-    def pause_worker(self, defer: Optional[bool]) -> None:
+    def pause_worker(self, defer: bool | None) -> None:
         return self._run_in_subprocess(pause_worker, [defer])
 
     def resume_worker(self) -> None:
         return self._run_in_subprocess(resume_worker)
 
-    def cancel_active_task(self, failure: bool, reason: Optional[str]) -> None:
+    def cancel_active_task(self, failure: bool, reason: str | None) -> None:
         return self._run_in_subprocess(cancel_active_task, [failure, reason])
 
     @property
     def tasks(self) -> list[TrackableTask]:
         return self._run_in_subprocess(tasks)
 
-    def get_task_by_id(self, task_id: str) -> Optional[TrackableTask]:
+    def get_task_by_id(self, task_id: str) -> TrackableTask | None:
         return self._run_in_subprocess(get_task_by_id, [task_id])
 
     @property
@@ -148,7 +145,7 @@ def begin_task(task: WorkerTask) -> WorkerTask:
     return get_handler().begin_task(task)
 
 
-def active_task() -> Optional[TrackableTask]:
+def active_task() -> TrackableTask | None:
     return get_handler().active_task
 
 
@@ -156,7 +153,7 @@ def state() -> WorkerState:
     return get_handler().state
 
 
-def pause_worker(defer: Optional[bool]) -> None:
+def pause_worker(defer: bool | None) -> None:
     return get_handler().pause_worker(defer)
 
 
@@ -164,7 +161,7 @@ def resume_worker() -> None:
     return get_handler().resume_worker()
 
 
-def cancel_active_task(failure: bool, reason: Optional[str]) -> None:
+def cancel_active_task(failure: bool, reason: str | None) -> None:
     return get_handler().cancel_active_task(failure, reason)
 
 
@@ -172,5 +169,5 @@ def tasks() -> list[TrackableTask]:
     return get_handler().tasks
 
 
-def get_task_by_id(task_id: str) -> Optional[TrackableTask]:
+def get_task_by_id(task_id: str) -> TrackableTask | None:
     return get_handler().get_task_by_id(task_id)
diff --git a/src/blueapi/startup/simmotor.py b/src/blueapi/startup/simmotor.py
index 49f143920..84067ba21 100644
--- a/src/blueapi/startup/simmotor.py
+++ b/src/blueapi/startup/simmotor.py
@@ -1,6 +1,6 @@
 import threading
 import time as ttime
-from typing import Callable, Optional
+from collections.abc import Callable
 
 from ophyd.sim import SynAxis
 from ophyd.status import MoveStatus, Status
@@ -13,7 +13,7 @@ def __init__(
         self,
         *,
         name: str,
-        readback_func: Optional[Callable] = None,
+        readback_func: Callable | None = None,
         value: float = 0.0,
         delay: float = 0.0,
         events_per_move: int = 6,
diff --git a/src/blueapi/utils/thread_exception.py b/src/blueapi/utils/thread_exception.py
index 988ee6dae..1151917fb 100644
--- a/src/blueapi/utils/thread_exception.py
+++ b/src/blueapi/utils/thread_exception.py
@@ -1,11 +1,12 @@
 import sys
 import traceback
+from collections.abc import Callable
 from functools import wraps
-from typing import Any, Callable, Optional
+from typing import Any
 
 
 def handle_all_exceptions(
-    func: Callable[..., Any], callback: Optional[Callable[[Exception], None]] = None
+    func: Callable[..., Any], callback: Callable[[Exception], None] | None = None
 ) -> Callable:
     """
     Ensure any uncaught exception traceback is printed to stdout. This does not
diff --git a/src/blueapi/worker/event.py b/src/blueapi/worker/event.py
index 2c14de30f..0ec8bb516 100644
--- a/src/blueapi/worker/event.py
+++ b/src/blueapi/worker/event.py
@@ -1,6 +1,5 @@
 from collections.abc import Mapping
 from enum import Enum
-from typing import Optional, Union
 
 from bluesky.run_engine import RunEngineStateMachine
 from pydantic import Field
@@ -9,7 +8,7 @@
 from blueapi.utils import BlueapiBaseModel
 
 # The RunEngine can return any of these three types as its state
-RawRunEngineState = Union[PropertyMachine, ProxyString, str]
+RawRunEngineState = type[PropertyMachine | ProxyString | str]
 
 
 class WorkerState(str, Enum):
@@ -53,13 +52,13 @@ class StatusView(BlueapiBaseModel):
         description="Human-readable name indicating what this status describes",
         default="Unknown",
     )
-    current: Optional[float] = Field(
+    current: float | None = Field(
         description="Current value of operation progress, if known", default=None
     )
-    initial: Optional[float] = Field(
+    initial: float | None = Field(
         description="Initial value of operation progress, if known", default=None
     )
-    target: Optional[float] = Field(
+    target: float | None = Field(
         description="Target value operation of progress, if known", default=None
     )
     unit: str = Field(description="Units of progress", default="units")
@@ -70,14 +69,14 @@ class StatusView(BlueapiBaseModel):
         description="Whether the operation this status describes is complete",
         default=False,
     )
-    percentage: Optional[float] = Field(
+    percentage: float | None = Field(
         description="Percentage of status completion, if known", default=None
     )
-    time_elapsed: Optional[float] = Field(
+    time_elapsed: float | None = Field(
         description="Time elapsed since status operation beginning, if known",
         default=None,
     )
-    time_remaining: Optional[float] = Field(
+    time_remaining: float | None = Field(
         description="Estimated time remaining until operation completion, if known",
         default=None,
     )
@@ -110,7 +109,7 @@ class WorkerEvent(BlueapiBaseModel):
     """
 
     state: WorkerState
-    task_status: Optional[TaskStatus] = None
+    task_status: TaskStatus | None = None
     errors: list[str] = Field(default_factory=list)
     warnings: list[str] = Field(default_factory=list)
 
diff --git a/src/blueapi/worker/multithread.py b/src/blueapi/worker/multithread.py
index ce2420ba2..cc02f884f 100644
--- a/src/blueapi/worker/multithread.py
+++ b/src/blueapi/worker/multithread.py
@@ -1,6 +1,6 @@
 import logging
 from concurrent.futures import Future, ThreadPoolExecutor
-from typing import Optional, TypeVar
+from typing import TypeVar
 
 from blueapi.core import configure_bluesky_event_loop
 from blueapi.utils import handle_all_exceptions
@@ -13,7 +13,7 @@
 
 
 def run_worker_in_own_thread(
-    worker: Worker[T], executor: Optional[ThreadPoolExecutor] = None
+    worker: Worker[T], executor: ThreadPoolExecutor | None = None
 ) -> Future:
     """
     Helper function, make a worker run in a new thread managed by a ThreadPoolExecutor
diff --git a/src/blueapi/worker/reworker.py b/src/blueapi/worker/reworker.py
index f284943db..97a523613 100644
--- a/src/blueapi/worker/reworker.py
+++ b/src/blueapi/worker/reworker.py
@@ -5,7 +5,7 @@
 from functools import partial
 from queue import Full, Queue
 from threading import Event, RLock
-from typing import Any, Optional, Union
+from typing import Any
 
 from bluesky.protocols import Status
 from super_state_machine.errors import TransitionError
@@ -55,7 +55,7 @@ class TaskWorker(Worker[Task]):
     _errors: list[str]
     _warnings: list[str]
     _task_channel: Queue  # type: ignore
-    _current: Optional[TrackableTask]
+    _current: TrackableTask | None
     _status_lock: RLock
     _status_snapshot: dict[str, StatusView]
     _completed_statuses: set[str]
@@ -101,7 +101,7 @@ def clear_task(self, task_id: str) -> str:
     def cancel_active_task(
         self,
         failure: bool = False,
-        reason: Optional[str] = None,
+        reason: str | None = None,
     ) -> str:
         if self._current is None:
             # Persuades mypy that self._current is not None
@@ -116,10 +116,10 @@ def cancel_active_task(
     def get_tasks(self) -> list[TrackableTask[Task]]:
         return list(self._tasks.values())
 
-    def get_task_by_id(self, task_id: str) -> Optional[TrackableTask[Task]]:
+    def get_task_by_id(self, task_id: str) -> TrackableTask[Task] | None:
         return self._tasks.get(task_id)
 
-    def get_active_task(self) -> Optional[TrackableTask[Task]]:
+    def get_active_task(self) -> TrackableTask[Task] | None:
         return self._current
 
     def begin_task(self, task_id: str) -> None:
@@ -142,7 +142,7 @@ def _submit_trackable_task(self, trackable_task: TrackableTask) -> None:
 
         task_started = Event()
 
-        def mark_task_as_started(event: WorkerEvent, _: Optional[str]) -> None:
+        def mark_task_as_started(event: WorkerEvent, _: str | None) -> None:
             if (
                 event.task_status is not None
                 and event.task_status.task_id == trackable_task.task_id
@@ -228,7 +228,7 @@ def _cycle_with_error_handling(self) -> None:
     def _cycle(self) -> None:
         try:
             LOGGER.info("Awaiting task")
-            next_task: Union[TrackableTask, KillSignal] = self._task_channel.get()
+            next_task: TrackableTask | KillSignal = self._task_channel.get()
             if isinstance(next_task, TrackableTask):
                 LOGGER.info(f"Got new task: {next_task}")
                 self._current = next_task  # Informing mypy that the task is not None
@@ -266,7 +266,7 @@ def data_events(self) -> EventStream[DataEvent, int]:
     def _on_state_change(
         self,
         raw_new_state: RawRunEngineState,
-        raw_old_state: Optional[RawRunEngineState] = None,
+        raw_old_state: RawRunEngineState | None = None,
     ) -> None:
         new_state = WorkerState.from_bluesky_state(raw_new_state)
         if raw_old_state:
@@ -286,7 +286,7 @@ def _report_error(self, err: Exception) -> None:
     def _report_status(
         self,
     ) -> None:
-        task_status: Optional[TaskStatus]
+        task_status: TaskStatus | None
         errors = self._errors
         warnings = self._warnings
         if self._current is not None:
@@ -319,7 +319,7 @@ def _on_document(self, name: str, document: Mapping[str, Any]) -> None:
                 "Trying to emit a document despite the fact that the RunEngine is idle"
             )
 
-    def _waiting_hook(self, statuses: Optional[Iterable[Status]]) -> None:
+    def _waiting_hook(self, statuses: Iterable[Status] | None) -> None:
         if statuses is not None:
             with self._status_lock:
                 for status in statuses:
@@ -347,15 +347,15 @@ def _on_status_event(
         status: Status,
         status_uuid: str,
         *,
-        name: Optional[str] = None,
-        current: Optional[float] = None,
-        initial: Optional[float] = None,
-        target: Optional[float] = None,
-        unit: Optional[str] = None,
-        precision: Optional[int] = None,
-        fraction: Optional[float] = None,
-        time_elapsed: Optional[float] = None,
-        time_remaining: Optional[float] = None,
+        name: str | None = None,
+        current: float | None = None,
+        initial: float | None = None,
+        target: float | None = None,
+        unit: str | None = None,
+        precision: int | None = None,
+        fraction: float | None = None,
+        time_elapsed: float | None = None,
+        time_remaining: float | None = None,
     ) -> None:
         if not status.done:
             percentage = float(1.0 - fraction) if fraction is not None else None
diff --git a/src/blueapi/worker/worker.py b/src/blueapi/worker/worker.py
index 84d73055c..026806074 100644
--- a/src/blueapi/worker/worker.py
+++ b/src/blueapi/worker/worker.py
@@ -1,5 +1,5 @@
 from abc import ABC, abstractmethod
-from typing import Generic, Optional, TypeVar
+from typing import Generic, TypeVar
 
 from pydantic import Field
 
@@ -40,7 +40,7 @@ def get_tasks(self) -> list[TrackableTask[T]]:
         """
 
     @abstractmethod
-    def get_task_by_id(self, task_id: str) -> Optional[TrackableTask[T]]:
+    def get_task_by_id(self, task_id: str) -> TrackableTask[T] | None:
         """
         Returns a task matching the task ID supplied,
         if the worker knows of it.
@@ -53,7 +53,7 @@ def get_task_by_id(self, task_id: str) -> Optional[TrackableTask[T]]:
                 None if the task ID is unknown to the worker.
         """
 
-    def get_active_task(self) -> Optional[TrackableTask[T]]:
+    def get_active_task(self) -> TrackableTask[T] | None:
         """
         Returns the task the worker is currently running
 
@@ -77,7 +77,7 @@ def clear_task(self, task_id: str) -> str:
     def cancel_active_task(
         self,
         failure: bool = False,
-        reason: Optional[str] = None,
+        reason: str | None = None,
     ) -> str:
         """
         Remove the currently active task from the worker if there is one
diff --git a/tests/preprocessors/test_attach_metadata.py b/tests/preprocessors/test_attach_metadata.py
index 878015922..8f879fc26 100644
--- a/tests/preprocessors/test_attach_metadata.py
+++ b/tests/preprocessors/test_attach_metadata.py
@@ -1,6 +1,6 @@
-from collections.abc import Mapping
+from collections.abc import Callable, Mapping
 from pathlib import Path
-from typing import Any, Callable
+from typing import Any
 
 import bluesky.plan_stubs as bps
 import bluesky.plans as bp
@@ -383,7 +383,7 @@ def assert_all_detectors_used_collection_numbers(
     descriptors = find_descriptor_docs(docs)
     assert len(descriptors) == len(source_history)
 
-    for descriptor, expected_source in zip(descriptors, source_history):
+    for descriptor, expected_source in zip(descriptors, source_history, strict=False):
         for detector in detectors:
             source = descriptor.doc.get("data_keys", {}).get(f"{detector.name}_data")[
                 "source"
diff --git a/tests/service/test_rest_api.py b/tests/service/test_rest_api.py
index 9c37b5359..ca416bae8 100644
--- a/tests/service/test_rest_api.py
+++ b/tests/service/test_rest_api.py
@@ -1,6 +1,5 @@
 import json
 from dataclasses import dataclass
-from typing import Optional
 from unittest.mock import MagicMock, call
 
 import pytest
@@ -346,7 +345,7 @@ def test_pausing_while_idle_denied(
 
 @pytest.mark.parametrize("defer", [True, False, None])
 def test_calls_pause_if_running(
-    mockable_state_machine: Handler, client: TestClient, defer: Optional[bool]
+    mockable_state_machine: Handler, client: TestClient, defer: bool | None
 ) -> None:
     re = mockable_state_machine._context.run_engine
     mockable_state_machine._worker._on_state_change(  # type: ignore
diff --git a/tests/service/test_subprocess_handler.py b/tests/service/test_subprocess_handler.py
index 147e845b4..4f9b00b65 100644
--- a/tests/service/test_subprocess_handler.py
+++ b/tests/service/test_subprocess_handler.py
@@ -1,4 +1,3 @@
-from typing import Optional
 from unittest.mock import MagicMock, patch
 
 import pytest
@@ -73,18 +72,18 @@ def begin_task(self, task: WorkerTask) -> WorkerTask:
         return WorkerTask(task_id=task.task_id)
 
     @property
-    def active_task(self) -> Optional[TrackableTask]:
+    def active_task(self) -> TrackableTask | None:
         return None
 
     @property
     def state(self) -> WorkerState:
         return WorkerState.IDLE
 
-    def pause_worker(self, defer: Optional[bool]) -> None: ...
+    def pause_worker(self, defer: bool | None) -> None: ...
 
     def resume_worker(self) -> None: ...
 
-    def cancel_active_task(self, failure: bool, reason: Optional[str]) -> None: ...
+    def cancel_active_task(self, failure: bool, reason: str | None) -> None: ...
 
     @property
     def tasks(self) -> list[TrackableTask]:
@@ -92,7 +91,7 @@ def tasks(self) -> list[TrackableTask]:
             TrackableTask(task_id="abc", task=Task(name="sleep", params={"time": 0.0}))
         ]
 
-    def get_task_by_id(self, task_id: str) -> Optional[TrackableTask]:
+    def get_task_by_id(self, task_id: str) -> TrackableTask | None:
         return None
 
     def start(self): ...
diff --git a/tests/worker/test_reworker.py b/tests/worker/test_reworker.py
index 2c65ef656..a31d7f3ec 100644
--- a/tests/worker/test_reworker.py
+++ b/tests/worker/test_reworker.py
@@ -1,9 +1,9 @@
 import itertools
 import threading
-from collections.abc import Iterable
+from collections.abc import Callable, Iterable
 from concurrent.futures import Future
 from queue import Full
-from typing import Any, Callable, Optional, TypeVar, Union
+from typing import Any, TypeVar
 from unittest.mock import MagicMock, patch
 
 import pytest
@@ -211,7 +211,7 @@ def test_produces_worker_events(worker: Worker, num_runs: int) -> None:
     task_ids = [worker.submit_task(_SIMPLE_TASK) for _ in range(num_runs)]
     event_sequences = [_sleep_events(task_id) for task_id in task_ids]
 
-    for task_id, events in zip(task_ids, event_sequences):
+    for task_id, events in zip(task_ids, event_sequences, strict=False):
         assert_run_produces_worker_events(events, worker, task_id)
 
 
@@ -344,7 +344,7 @@ def test_worker_and_data_events_produce_in_order(worker: Worker) -> None:
 
 
 def assert_running_count_plan_produces_ordered_worker_and_data_events(
-    expected_events: list[Union[WorkerEvent, DataEvent]],
+    expected_events: list[WorkerEvent | DataEvent],
     worker: Worker,
     task: Task = Task(name="count", params={"detectors": ["image_det"], "num": 1}),  # noqa: B008
     timeout: float = 5.0,
@@ -392,7 +392,7 @@ def take_events(
     events: list[E] = []
     future: "Future[list[E]]" = Future()
 
-    def on_event(event: E, event_id: Optional[str]) -> None:
+    def on_event(event: E, event_id: str | None) -> None:
         events.append(event)
         if cutoff_predicate(event):
             future.set_result(events)
@@ -428,7 +428,7 @@ def take_events_from_streams(
     events: list[Any] = []
     future: "Future[list[Any]]" = Future()
 
-    def on_event(event: Any, event_id: Optional[str]) -> None:
+    def on_event(event: Any, event_id: str | None) -> None:
         print(event)
         events.append(event)
         if cutoff_predicate(event):