diff --git a/.github/workflows/test.yaml b/.github/workflows/test.yaml
index d866aff..a42c5ae 100644
--- a/.github/workflows/test.yaml
+++ b/.github/workflows/test.yaml
@@ -31,12 +31,13 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - python-version: "3.8"
-            pip-install-spec: "jupyterhub==2.3.1 sqlalchemy==1.*"
+          # jupyterhub 4 works with pytest-asyncio 0.25
+          # but requires some deprecated features,
+          # so don't let it upgrade further
           - python-version: "3.9"
-            pip-install-spec: "jupyterhub==3.*"
+            pip-install-spec: "jupyterhub==4.* sqlalchemy==1.* pytest-asyncio==0.25.*"
           - python-version: "3.11"
-            pip-install-spec: "jupyterhub==4.*"
+            pip-install-spec: "jupyterhub==4.* pytest-asyncio==0.25.*"
             test-variation: podman
           - python-version: "3.12"
             pip-install-spec: "jupyterhub==5.*"
diff --git a/README.md b/README.md
index 9ed0db6..46caeb2 100644
--- a/README.md
+++ b/README.md
@@ -25,7 +25,7 @@ for more information about features and usage.
 
 ## Prerequisites
 
-Python 3.8 or above and JupyterHub 2.3.1 or above is required.
+Python 3.9 or above and JupyterHub 4 or above is required.
 
 ## Installation
 
diff --git a/dev-requirements.txt b/dev-requirements.txt
index b899b3e..5f57b65 100644
--- a/dev-requirements.txt
+++ b/dev-requirements.txt
@@ -1,6 +1,5 @@
 netifaces
 notebook<7
 pytest>=3.6
-# FIXME: unpin pytest-asyncio
-pytest-asyncio>=0.17,<0.23
+pytest-asyncio>=0.25
 pytest-cov
diff --git a/pyproject.toml b/pyproject.toml
index 41a2d93..7b76a17 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -24,7 +24,6 @@ profile = "black"
 [tool.black]
 skip-string-normalization = true
 target_version = [
-    "py38",
     "py39",
     "py310",
     "py311",
@@ -38,6 +37,7 @@ target_version = [
 [tool.pytest.ini_options]
 addopts = "--verbose --color=yes --durations=10 --maxfail=1"
 asyncio_mode = "auto"
+asyncio_default_fixture_loop_scope = "module"
 testpaths = ["tests"]
 # These markers are registered to avoid warnings triggered by importing from
 # jupyterhub.tests.test_api.
diff --git a/requirements.txt b/requirements.txt
index 2e2c051..8964868 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,3 +1,3 @@
 docker
 escapism
-jupyterhub>=2.3.1
+jupyterhub>=4
diff --git a/setup.py b/setup.py
index 6fde6fc..ef81d24 100644
--- a/setup.py
+++ b/setup.py
@@ -71,7 +71,7 @@ def run(self):
             'docker-swarm = dockerspawner:SwarmSpawner',
         ],
     },
-    python_requires=">=3.8",
+    python_requires=">=3.9",
     cmdclass={
         'bdist_egg': bdist_egg if 'bdist_egg' in sys.argv else bdist_egg_disabled,
     },
diff --git a/tests/conftest.py b/tests/conftest.py
index b79dbbe..cd266c6 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -9,16 +9,20 @@
 import jupyterhub
 import netifaces
 import pytest
+import pytest_asyncio
 from docker import from_env as docker_from_env
 from docker.errors import APIError
 from jupyterhub import version_info as jh_version_info
 from jupyterhub.tests.conftest import app as jupyterhub_app  # noqa: F401
-from jupyterhub.tests.conftest import event_loop  # noqa: F401
 from jupyterhub.tests.conftest import io_loop  # noqa: F401
 from jupyterhub.tests.conftest import ssl_tmpdir  # noqa: F401
 from jupyterhub.tests.conftest import user  # noqa: F401
 from jupyterhub.tests.mocking import MockHub
 
+if 'event_loop' in inspect.signature(io_loop).parameters:
+    # older JupyterHub (< 5.x), io_loop requires deprecated event_loop
+    from jupyterhub.tests.conftest import event_loop  # noqa: F401
+
 from dockerspawner import DockerSpawner, SwarmSpawner, SystemUserSpawner
 
 # import base jupyterhub fixtures
@@ -46,16 +50,19 @@
 
 
 def pytest_collection_modifyitems(items):
-    """This function is automatically run by pytest passing all collected test
-    functions.
-
-    We use it to add asyncio marker to all async tests and assert we don't use
-    test functions that are async generators which wouldn't make sense.
-    """
-    for item in items:
-        if inspect.iscoroutinefunction(item.obj):
-            item.add_marker('asyncio')
-        assert not inspect.isasyncgenfunction(item.obj)
+    # apply loop_scope="module" to all async tests by default
+    # this can be hopefully be removed in favor of config if
+    # https://github.com/pytest-dev/pytest-asyncio/issues/793
+    # is addressed
+    pytest_asyncio_tests = (
+        item for item in items if pytest_asyncio.is_async_test(item)
+    )
+    asyncio_scope_marker = pytest.mark.asyncio(loop_scope="module")
+    for async_test in pytest_asyncio_tests:
+        # add asyncio marker _if_ not already present
+        asyncio_marker = async_test.get_closest_marker('asyncio')
+        if not asyncio_marker or not asyncio_marker.kwargs:
+            async_test.add_marker(asyncio_scope_marker, append=False)
 
 
 @pytest.fixture
@@ -89,9 +96,10 @@ def dockerspawner_configured_app(app, named_servers):
 @pytest.fixture
 def swarmspawner_configured_app(app, named_servers):
     """Configure JupyterHub to use DockerSpawner"""
-    with mock.patch.dict(
-        app.tornado_settings, {"spawner_class": SwarmSpawner}
-    ), mock.patch.dict(app.config.SwarmSpawner, {"network_name": "bridge"}):
+    with (
+        mock.patch.dict(app.tornado_settings, {"spawner_class": SwarmSpawner}),
+        mock.patch.dict(app.config.SwarmSpawner, {"network_name": "bridge"}),
+    ):
         yield app