diff --git a/.github/workflows/nox.yml b/.github/workflows/nox.yml
index f021d3b2c..a03b2d7b2 100644
--- a/.github/workflows/nox.yml
+++ b/.github/workflows/nox.yml
@@ -12,7 +12,7 @@ jobs:
       fail-fast: false
       matrix:
         platform: [ubuntu-latest, macos-latest, windows-latest]
-        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
+        python-version: ["3.11", "3.12", "3.13"]
 
     steps:
     - uses: actions/checkout@v4
diff --git a/adaptive/learner/average_learner.py b/adaptive/learner/average_learner.py
index c3d4892b4..3252530b4 100644
--- a/adaptive/learner/average_learner.py
+++ b/adaptive/learner/average_learner.py
@@ -1,7 +1,7 @@
 from __future__ import annotations
 
+from collections.abc import Callable
 from math import sqrt
-from typing import Callable
 
 import cloudpickle
 import numpy as np
diff --git a/adaptive/learner/average_learner1D.py b/adaptive/learner/average_learner1D.py
index 9678b4f64..cb844f011 100644
--- a/adaptive/learner/average_learner1D.py
+++ b/adaptive/learner/average_learner1D.py
@@ -3,10 +3,9 @@
 import math
 import sys
 from collections import defaultdict
-from collections.abc import Iterable, Sequence
+from collections.abc import Callable, Iterable, Sequence
 from copy import deepcopy
 from math import hypot
-from typing import Callable
 
 import numpy as np
 import scipy.stats
diff --git a/adaptive/learner/balancing_learner.py b/adaptive/learner/balancing_learner.py
index e9a4a661e..b8a340f95 100644
--- a/adaptive/learner/balancing_learner.py
+++ b/adaptive/learner/balancing_learner.py
@@ -1,13 +1,12 @@
 from __future__ import annotations
 
 import itertools
-import sys
 from collections import defaultdict
-from collections.abc import Iterable, Sequence
+from collections.abc import Callable, Iterable, Sequence
 from contextlib import suppress
 from functools import partial
 from operator import itemgetter
-from typing import Any, Callable, Union, cast
+from typing import Any, Literal, TypeAlias, cast
 
 import numpy as np
 
@@ -16,13 +15,6 @@
 from adaptive.types import Int, Real
 from adaptive.utils import cache_latest, named_product, restore
 
-if sys.version_info >= (3, 10):
-    from typing import TypeAlias
-else:
-    from typing_extensions import TypeAlias
-
-from typing import Literal
-
 try:
     import pandas
 
@@ -38,11 +30,9 @@ def dispatch(child_functions: list[Callable], arg: Any) -> Any:
 
 STRATEGY_TYPE: TypeAlias = Literal["loss_improvements", "loss", "npoints", "cycle"]
 
-CDIMS_TYPE: TypeAlias = Union[
-    Sequence[dict[str, Any]],
-    tuple[Sequence[str], Sequence[tuple[Any, ...]]],
-    None,
-]
+CDIMS_TYPE: TypeAlias = (
+    Sequence[dict[str, Any]] | tuple[Sequence[str], Sequence[tuple[Any, ...]]] | None
+)
 
 
 class BalancingLearner(BaseLearner):
diff --git a/adaptive/learner/base_learner.py b/adaptive/learner/base_learner.py
index 73720dd52..f5ef73eca 100644
--- a/adaptive/learner/base_learner.py
+++ b/adaptive/learner/base_learner.py
@@ -1,8 +1,9 @@
 from __future__ import annotations
 
 import abc
+from collections.abc import Callable
 from contextlib import suppress
-from typing import TYPE_CHECKING, Any, Callable, TypeVar
+from typing import TYPE_CHECKING, Any, TypeVar
 
 import cloudpickle
 
diff --git a/adaptive/learner/data_saver.py b/adaptive/learner/data_saver.py
index a69807389..644691a57 100644
--- a/adaptive/learner/data_saver.py
+++ b/adaptive/learner/data_saver.py
@@ -2,7 +2,8 @@
 
 import functools
 from collections import OrderedDict
-from typing import Any, Callable
+from collections.abc import Callable
+from typing import Any
 
 from adaptive.learner.base_learner import BaseLearner, LearnerType
 from adaptive.utils import copy_docstring_from
diff --git a/adaptive/learner/integrator_learner.py b/adaptive/learner/integrator_learner.py
index 0fc97df67..d6ee9ef1d 100644
--- a/adaptive/learner/integrator_learner.py
+++ b/adaptive/learner/integrator_learner.py
@@ -3,9 +3,10 @@
 
 import sys
 from collections import defaultdict
+from collections.abc import Callable
 from math import sqrt
 from operator import attrgetter
-from typing import TYPE_CHECKING, Callable
+from typing import TYPE_CHECKING
 
 import cloudpickle
 import numpy as np
diff --git a/adaptive/learner/learner1D.py b/adaptive/learner/learner1D.py
index bf04743bd..6cd88b4ad 100644
--- a/adaptive/learner/learner1D.py
+++ b/adaptive/learner/learner1D.py
@@ -3,10 +3,9 @@
 import collections.abc
 import itertools
 import math
-import sys
-from collections.abc import Sequence
+from collections.abc import Callable, Sequence
 from copy import copy, deepcopy
-from typing import TYPE_CHECKING, Any, Callable, Optional, Union
+from typing import TYPE_CHECKING, Any, TypeAlias
 
 import cloudpickle
 import numpy as np
@@ -24,12 +23,6 @@
     partial_function_from_dataframe,
 )
 
-if sys.version_info >= (3, 10):
-    from typing import TypeAlias
-else:
-    from typing_extensions import TypeAlias
-
-
 try:
     import pandas
 
@@ -42,28 +35,21 @@
     # -- types --
 
     # Commonly used types
-    Interval: TypeAlias = Union[tuple[float, float], tuple[float, float, int]]
-    NeighborsType: TypeAlias = SortedDict[float, list[Optional[float]]]
+    Interval: TypeAlias = tuple[float, float] | tuple[float, float, int]
+    NeighborsType: TypeAlias = SortedDict[float, list[float | None]]
 
     # Types for loss_per_interval functions
     XsType0: TypeAlias = tuple[float, float]
-    YsType0: TypeAlias = Union[tuple[float, float], tuple[np.ndarray, np.ndarray]]
-    XsType1: TypeAlias = tuple[
-        Optional[float], Optional[float], Optional[float], Optional[float]
-    ]
-    YsType1: TypeAlias = Union[
-        tuple[Optional[float], Optional[float], Optional[float], Optional[float]],
-        tuple[
-            Optional[np.ndarray],
-            Optional[np.ndarray],
-            Optional[np.ndarray],
-            Optional[np.ndarray],
-        ],
-    ]
-    XsTypeN: TypeAlias = tuple[Optional[float], ...]
-    YsTypeN: TypeAlias = Union[
-        tuple[Optional[float], ...], tuple[Optional[np.ndarray], ...]
-    ]
+    YsType0: TypeAlias = tuple[float, float] | tuple[np.ndarray, np.ndarray]
+    XsType1: TypeAlias = tuple[float | None, float | None, float | None, float | None]
+    YsType1: TypeAlias = (
+        tuple[float | None, float | None, float | None, float | None]
+        | tuple[
+            np.ndarray | None, np.ndarray | None, np.ndarray | None, np.ndarray | None
+        ]
+    )
+    XsTypeN: TypeAlias = tuple[float | None, ...]
+    YsTypeN: TypeAlias = tuple[float | None, ...] | tuple[np.ndarray | None, ...]
 
 
 __all__ = [
@@ -598,7 +584,7 @@ def tell(self, x: float, y: Float | Sequence[Float] | np.ndarray) -> None:
             )
 
         # either it is a float/int, if not, try casting to a np.array
-        if not isinstance(y, (float, int)):
+        if not isinstance(y, float | int):
             y = np.asarray(y, dtype=float)
 
         # Add point to the real data dict
diff --git a/adaptive/learner/learner2D.py b/adaptive/learner/learner2D.py
index 15864a808..49b9cef56 100644
--- a/adaptive/learner/learner2D.py
+++ b/adaptive/learner/learner2D.py
@@ -3,10 +3,9 @@
 import itertools
 import warnings
 from collections import OrderedDict
-from collections.abc import Iterable
+from collections.abc import Callable, Iterable
 from copy import copy
 from math import sqrt
-from typing import Callable
 
 import cloudpickle
 import numpy as np
diff --git a/adaptive/learner/sequence_learner.py b/adaptive/learner/sequence_learner.py
index c307744fd..e8d83af5d 100644
--- a/adaptive/learner/sequence_learner.py
+++ b/adaptive/learner/sequence_learner.py
@@ -1,8 +1,7 @@
 from __future__ import annotations
 
-import sys
 from copy import copy
-from typing import TYPE_CHECKING, Any
+from typing import TYPE_CHECKING, Any, TypeAlias
 
 import cloudpickle
 from sortedcontainers import SortedDict, SortedSet
@@ -16,8 +15,7 @@
 )
 
 if TYPE_CHECKING:
-    from collections.abc import Sequence
-    from typing import Callable
+    from collections.abc import Callable, Sequence
 
 try:
     import pandas
@@ -27,10 +25,6 @@
 except ModuleNotFoundError:
     with_pandas = False
 
-if sys.version_info >= (3, 10):
-    from typing import TypeAlias
-else:
-    from typing_extensions import TypeAlias
 
 PointType: TypeAlias = tuple[Int, Any]
 
diff --git a/adaptive/runner.py b/adaptive/runner.py
index 4f877096f..592fca4a1 100644
--- a/adaptive/runner.py
+++ b/adaptive/runner.py
@@ -8,77 +8,48 @@
 import itertools
 import pickle
 import platform
-import sys
 import time
 import traceback
 import warnings
+from collections.abc import Callable
 from contextlib import suppress
 from datetime import datetime, timedelta
 from importlib.util import find_spec
-from typing import TYPE_CHECKING, Any, Callable, Literal, Optional, Union
+from typing import TYPE_CHECKING, Any, Literal, TypeAlias
 
 import loky
 
-from adaptive import (
-    BalancingLearner,
-    DataSaver,
-    IntegratorLearner,
-    SequenceLearner,
-)
+from adaptive import BalancingLearner, DataSaver, IntegratorLearner, SequenceLearner
 from adaptive.learner.base_learner import LearnerType
 from adaptive.notebook_integration import in_ipynb, live_info, live_plot
 from adaptive.utils import SequentialExecutor
 
-ExecutorTypes: TypeAlias = Union[
-    concurrent.ProcessPoolExecutor,
-    concurrent.ThreadPoolExecutor,
-    SequentialExecutor,
-    loky.reusable_executor._ReusablePoolExecutor,
-]
-FutureTypes: TypeAlias = Union[concurrent.Future, asyncio.Future, asyncio.Task]
-
 if TYPE_CHECKING:
     import holoviews
 
 
-if sys.version_info >= (3, 10):
-    from typing import TypeAlias
-else:
-    from typing_extensions import TypeAlias
-
-
 with_ipyparallel = find_spec("ipyparallel") is not None
 with_distributed = find_spec("distributed") is not None
 with_mpi4py = find_spec("mpi4py") is not None
 
 if TYPE_CHECKING:
-    ExecutorTypes = Optional[()]
-    FutureTypes = Optional[()]
-
-    if with_distributed:
-        import distributed
-
-        ExecutorTypes = Optional[
-            Union[
-                ExecutorTypes, distributed.Client, distributed.cfexecutor.ClientExecutor
-            ]
-        ]
-
-    if with_mpi4py:
-        import mpi4py.futures
-
-        ExecutorTypes = Optional[Union[ExecutorTypes, mpi4py.futures.MPIPoolExecutor]]
-
-    if with_ipyparallel:
-        import ipyparallel
-        from ipyparallel.client.asyncresult import AsyncResult
+    import distributed
+    import ipyparallel
+    import mpi4py.futures
+
+    ExecutorTypes: TypeAlias = (
+        concurrent.ProcessPoolExecutor
+        | concurrent.ThreadPoolExecutor
+        | SequentialExecutor
+        | loky.reusable_executor._ReusablePoolExecutor
+        | distributed.Client
+        | distributed.cfexecutor.ClientExecutor
+        | mpi4py.futures.MPIPoolExecutor
+        | ipyparallel.Client
+        | ipyparallel.client.view.ViewExecutor
+    )
+    FutureTypes: TypeAlias = concurrent.Future | asyncio.Future
 
-        ExecutorTypes = Optional[
-            Union[
-                ExecutorTypes, ipyparallel.Client, ipyparallel.client.view.ViewExecutor
-            ]
-        ]
-        FutureTypes = Optional[Union[FutureTypes, AsyncResult]]
 
 with suppress(ModuleNotFoundError):
     import uvloop
@@ -203,7 +174,7 @@ def __init__(
 
         self._max_tasks = ntasks
 
-        self._pending_tasks: dict[concurrent.Future, int] = {}
+        self._pending_tasks: dict[FutureTypes, int] = {}
 
         # if we instantiate our own executor, then we are also responsible
         # for calling 'shutdown'
@@ -292,7 +263,8 @@ def _process_futures(
             pid = self._pending_tasks.pop(fut)
             try:
                 y = fut.result()
-                t = time.time() - fut.start_time  # total execution time
+                # total execution time
+                t = time.time() - fut.start_time  # type: ignore[union-attr]
             except Exception as e:
                 self._tracebacks[pid] = traceback.format_exc()
                 self._to_retry[pid] = self._to_retry.get(pid, 0) + 1
@@ -508,12 +480,12 @@ def _run(self) -> None:
         try:
             while not self.goal(self.learner):
                 futures = self._get_futures()
-                done, _ = concurrent.wait(futures, return_when=first_completed)
-                self._process_futures(done)
+                done, _ = concurrent.wait(futures, return_when=first_completed)  # type: ignore[arg-type]
+                self._process_futures(done)  # type: ignore[arg-type]
         finally:
             remaining = self._remove_unfinished()
             if remaining:
-                concurrent.wait(remaining)
+                concurrent.wait(remaining)  # type: ignore[arg-type]
                 # Some futures get their result set, despite being cancelled.
                 # see https://github.com/python-adaptive/adaptive/issues/319
                 with_result = {f for f in remaining if not f.cancelled() and f.done()}
@@ -835,13 +807,12 @@ async def _run(self) -> None:
         try:
             while not self.goal(self.learner):
                 futures = self._get_futures()
-                kw = {"loop": self.ioloop} if sys.version_info[:2] < (3, 10) else {}
-                done, _ = await asyncio.wait(futures, return_when=first_completed, **kw)  # type: ignore[arg-type]
+                done, _ = await asyncio.wait(futures, return_when=first_completed)  # type: ignore[arg-type,type-var]
                 self._process_futures(done)
         finally:
             remaining = self._remove_unfinished()
             if remaining:
-                await asyncio.wait(remaining)
+                await asyncio.wait(remaining)  # type: ignore[type-var]
             self._cleanup()
 
     def elapsed_time(self) -> float:
@@ -1062,9 +1033,7 @@ def _get_ncores(
         import mpi4py.futures
     if with_ipyparallel and isinstance(ex, ipyparallel.client.view.ViewExecutor):
         return len(ex.view)
-    elif isinstance(
-        ex, (concurrent.ProcessPoolExecutor, concurrent.ThreadPoolExecutor)
-    ):
+    elif isinstance(ex, concurrent.ProcessPoolExecutor | concurrent.ThreadPoolExecutor):
         return ex._max_workers  # type: ignore[union-attr]
     elif isinstance(ex, loky.reusable_executor._ReusablePoolExecutor):
         return ex._max_workers  # type: ignore[union-attr]
@@ -1119,7 +1088,7 @@ def stop_after(*, seconds=0, minutes=0, hours=0) -> Callable[[LearnerType], bool
 
 class _TimeGoal:
     def __init__(self, dt: timedelta | datetime | int | float):
-        self.dt = dt if isinstance(dt, (timedelta, datetime)) else timedelta(seconds=dt)
+        self.dt = dt if isinstance(dt, timedelta | datetime) else timedelta(seconds=dt)
         self.start_time = None
 
     def __call__(self, _):
diff --git a/adaptive/tests/algorithm_4.py b/adaptive/tests/algorithm_4.py
index 27832298e..8741fdc53 100644
--- a/adaptive/tests/algorithm_4.py
+++ b/adaptive/tests/algorithm_4.py
@@ -3,8 +3,8 @@
 from __future__ import annotations
 
 from collections import defaultdict
+from collections.abc import Callable
 from fractions import Fraction
-from typing import Callable
 
 import numpy as np
 from numpy.testing import assert_allclose
diff --git a/adaptive/tests/test_average_learner1d.py b/adaptive/tests/test_average_learner1d.py
index c0148c5e9..a9be7fce2 100644
--- a/adaptive/tests/test_average_learner1d.py
+++ b/adaptive/tests/test_average_learner1d.py
@@ -21,7 +21,7 @@ def almost_equal_dicts(a, b):
         if (
             v1 is None
             or v2 is None
-            or isinstance(v1, (tuple, list))
+            or isinstance(v1, tuple | list)
             and any(x is None for x in chain(v1, v2))
         ):
             assert v1 == v2
diff --git a/adaptive/tests/test_notebook_integration.py b/adaptive/tests/test_notebook_integration.py
index 3e4ddb298..2fb266f2a 100644
--- a/adaptive/tests/test_notebook_integration.py
+++ b/adaptive/tests/test_notebook_integration.py
@@ -1,7 +1,5 @@
 from __future__ import annotations
 
-import os
-import sys
 from typing import TYPE_CHECKING
 
 import pytest
@@ -16,13 +14,9 @@
 except ImportError:
     with_notebook_dependencies = False
 
-# XXX: remove when is fixed https://github.com/ipython/ipykernel/issues/468
-skip_because_of_bug = os.name == "nt" and sys.version_info[:2] == (3, 8)
-
 
 @pytest.mark.skipif(
-    not with_notebook_dependencies or skip_because_of_bug,
-    reason="notebook dependencies are not installed",
+    not with_notebook_dependencies, reason="notebook dependencies are not installed"
 )
 def test_private_api_used_in_live_info():
     """We are catching all errors in
diff --git a/adaptive/types.py b/adaptive/types.py
index 367445ee4..e2869d46e 100644
--- a/adaptive/types.py
+++ b/adaptive/types.py
@@ -1,17 +1,11 @@
-import sys
-from typing import Union
+from typing import TypeAlias
 
 import numpy as np
 
-if sys.version_info >= (3, 10):
-    from typing import TypeAlias
-else:
-    from typing_extensions import TypeAlias
-
-Float: TypeAlias = Union[float, np.float64]
-Bool: TypeAlias = Union[bool, np.bool_]
-Int: TypeAlias = Union[int, np.int_]
-Real: TypeAlias = Union[Float, Int]
+Float: TypeAlias = float | np.float64
+Bool: TypeAlias = bool | np.bool_
+Int: TypeAlias = int | np.int_
+Real: TypeAlias = Float | Int
 
 
 __all__ = ["Float", "Bool", "Int", "Real"]
diff --git a/adaptive/utils.py b/adaptive/utils.py
index ff80f62f1..2a1680cac 100644
--- a/adaptive/utils.py
+++ b/adaptive/utils.py
@@ -7,11 +7,11 @@
 import os
 import pickle
 import warnings
-from collections.abc import Awaitable, Iterator, Sequence
+from collections.abc import Awaitable, Callable, Iterator, Sequence
 from contextlib import contextmanager
 from functools import wraps
 from itertools import product
-from typing import TYPE_CHECKING, Any, Callable, TypeVar
+from typing import TYPE_CHECKING, Any, TypeVar
 
 import cloudpickle
 
diff --git a/docs/environment.yml b/docs/environment.yml
index 3e99ae627..caa8badcf 100644
--- a/docs/environment.yml
+++ b/docs/environment.yml
@@ -4,7 +4,7 @@ channels:
   - conda-forge
 
 dependencies:
-  - python=3.10
+  - python=3.11
   - sortedcollections=2.1.0
   - scipy=1.10.1
   - holoviews=1.18.3
diff --git a/docs/source/algorithms_and_examples.md b/docs/source/algorithms_and_examples.md
index eda3c2fff..0aff9f1fa 100644
--- a/docs/source/algorithms_and_examples.md
+++ b/docs/source/algorithms_and_examples.md
@@ -4,7 +4,7 @@ jupytext:
     extension: .md
     format_name: myst
     format_version: 0.13
-    jupytext_version: 1.14.5
+    jupytext_version: 1.17.1
 kernelspec:
   display_name: python3
   name: python3
diff --git a/docs/source/tutorial/tutorial.LearnerND.md b/docs/source/tutorial/tutorial.LearnerND.md
index 46f948708..37705b79d 100644
--- a/docs/source/tutorial/tutorial.LearnerND.md
+++ b/docs/source/tutorial/tutorial.LearnerND.md
@@ -4,7 +4,7 @@ jupytext:
     extension: .md
     format_name: myst
     format_version: 0.13
-    jupytext_version: 1.14.5
+    jupytext_version: 1.17.1
 kernelspec:
   display_name: python3
   name: python3
diff --git a/environment.yml b/environment.yml
index a31560f15..1dfb8c86d 100644
--- a/environment.yml
+++ b/environment.yml
@@ -4,7 +4,7 @@ channels:
 - conda-forge
 
 dependencies:
-  - python=3.9
+  - python=3.13
   - sortedcontainers
   - sortedcollections
   - scipy
diff --git a/noxfile.py b/noxfile.py
index 6a6114bb3..71a2217a4 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -6,7 +6,7 @@
 
 nox.options.default_venv_backend = "uv"
 
-python = ["3.9", "3.10", "3.11", "3.12", "3.13"]
+python = ["3.11", "3.12", "3.13"]
 num_cpus = os.cpu_count() or 1
 xdist = ("-n", "auto") if num_cpus > 2 else ()
 
diff --git a/pyproject.toml b/pyproject.toml
index 5e59cad3b..5c7186e98 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -8,15 +8,14 @@ dynamic = ["version"]
 description = "Parallel active learning of mathematical functions"
 maintainers = [{ name = "Adaptive authors" }]
 license = { text = "BSD" }
-requires-python = ">=3.9"
+requires-python = ">=3.11"
 classifiers = [
     "Development Status :: 4 - Beta",
     "License :: OSI Approved :: BSD License",
     "Intended Audience :: Science/Research",
-    "Programming Language :: Python :: 3.9",
-    "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",
+    "Programming Language :: Python :: 3.13",
 ]
 dependencies = [
     "scipy",
@@ -24,7 +23,6 @@ dependencies = [
     "sortedcontainers >= 2.0",
     "cloudpickle",
     "loky >= 2.9",
-    "typing_extensions; python_version < '3.10'",
     "versioningit",
 ]
 
@@ -100,11 +98,11 @@ output = ".coverage.xml"
 
 [tool.mypy]
 ignore_missing_imports = true
-python_version = "3.9"
+python_version = "3.11"
 
 [tool.ruff]
 line-length = 88
-target-version = "py39"
+target-version = "py311"
 
 [tool.ruff.lint]
 select = ["B", "C", "E", "F", "W", "T", "B9", "I", "UP"]
@@ -118,6 +116,7 @@ ignore = [
     "PLW0603", # Using the global statement to update `X` is discouraged
     "D401",    # First line of docstring should be in imperative mood
     "E501",    # Line too long
+    "B905",    # `zip()` without an explicit `strict=` parameter
 ]
 
 [tool.ruff.lint.mccabe]