diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index ce9e18e..a3cab57 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -2,10 +2,11 @@ name: Build and Test
 
 on:
   push:
+    branches:
+      - master
   pull_request:
     branches:
       - master
-    types: [closed]
 
 jobs:
   matrix-builder:
@@ -24,7 +25,7 @@ jobs:
         env:
           PY_VERSIONS: "[\"3.7\", \"3.8\", \"3.9\", \"3.10\", \"3.11\", \"pypy-3.8-v7.3.11\", \"pypy-3.9-v7.3.11\"]"
           OS_NAMES: "[\"ubuntu-20.04\"]"  #, windows-latest, macOS-latest]
-          CELERY_VERSIONS: "[\">=3.1.0,<4.0.0\", \">=4.0.0,<5.0.0\", \">=5.0.0,<6.0.0\"]"
+          CELERY_VERSIONS: "[\">=4.0.0,<5.0.0\", \">=5.0.0,<6.0.0\"]"
         run: |
           python -m pip install --upgrade pip
           MATRIX=$(python .github/workflows/resolve_versions.py matrix -c "$PY_VERSIONS" -o "$OS_NAMES" -n "celery" -s "$CELERY_VERSIONS")
@@ -109,6 +110,9 @@ jobs:
         pip install "celery${{ matrix.celery }}"
         pip install pytest-github-actions-annotate-failures
 
+    - name: Check with black
+      run: black --check .
+
     - name: Check with mypy
       if: ${{ !startsWith(matrix.python-version, 'pypy') && matrix.python-version >= '3.7' }}
       run: mypy
diff --git a/.github/workflows/resolve_versions.py b/.github/workflows/resolve_versions.py
index 932df8f..c8e787a 100644
--- a/.github/workflows/resolve_versions.py
+++ b/.github/workflows/resolve_versions.py
@@ -127,19 +127,7 @@ def process_matrix(args: Namespace) -> None:
     for c, o, n, s in matrix:
         compatible_versions = get_compatible_versions(c, o, n, s)
         if compatible_versions:
-            # This is because celery 3 depends on use_2to3,
-            # which is no longer supported by 3.9, 3.10 and 3.11
-            # and by newer pypy versions.
             if (
-                n == "celery"
-                and (
-                    c.replace(".", "").startswith("39")
-                    or c.replace(".", "").startswith("310")
-                    or c.replace(".", "").startswith("311")
-                    or c.startswith("pypy-3")
-                )
-                and all(cv.startswith("3") for cv in compatible_versions)
-            ) or (
                 # This is because inspect.getfullargspec has been removed in Python 3.11
                 # and `vine.five` 4.x was depending on it. This is fixed in 5.x.
                 n == "celery"
diff --git a/README.md b/README.md
index 303a1c1..2579cac 100644
--- a/README.md
+++ b/README.md
@@ -103,6 +103,7 @@ celery_pubsub.publish('some.very.good.test', 42)  # task 3 only
 * 2.0.0
     * Drop support for CPython 2.7, 3.4, 3.5, 3.6
     * Drop support for Pypy 2.7 and 3.6.
+    * Drop support for Celery 3.
     * Add support for Pypy 3.8 and 3.9.
     * Add support for CPython 3.11.
     * Type hints are now directly in the code. No more stubs files.
diff --git a/requirements.txt b/requirements.txt
index 0c3a687..6c9d576 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1 +1 @@
-celery>=3.1.0
+celery>=4.0.0
diff --git a/tests/conftest.py b/tests/conftest.py
index 519483f..0801200 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -20,9 +20,9 @@
 
 import celery
 from celery import Task
-from celery.worker import WorkController
 
 from celery_pubsub import subscribe, subscribe_to
+from celery_pubsub import subscribe
 from pkg_resources import get_distribution, parse_version
 
 P = ParamSpec("P")
@@ -30,29 +30,18 @@
 task: Callable[..., Callable[[Callable[P, R]], Task[P, R]]]
 
 if not typing.TYPE_CHECKING:
-    if get_distribution("celery").parsed_version < parse_version("4.0.0"):
-        celery.current_app.conf.update(
-            CELERY_ALWAYS_EAGER=True,
-        )
-        task = celery.task
+    task = celery.shared_task
 
-        @pytest.fixture
-        def celery_worker() -> WorkController:
-            pass
+    @pytest.fixture(scope="session")
+    def celery_config():
+        return {
+            "broker_url": "memory://",
+            "result_backend": "rpc://",
+            "broker_transport_options": {"polling_interval": 0.05},
+        }
 
-    else:  # pragma: no cover
-        task = celery.shared_task
-
-        @pytest.fixture(scope="session")
-        def celery_config():
-            return {
-                "broker_url": "memory://",
-                "result_backend": "rpc://",
-                "broker_transport_options": {"polling_interval": 0.05},
-            }
-
-        if get_distribution("celery").parsed_version >= parse_version("5.0.0"):
-            pytest_plugins = ["celery.contrib.pytest"]
+    if get_distribution("celery").parsed_version >= parse_version("5.0.0"):
+        pytest_plugins = ["celery.contrib.pytest"]
 
 
 @pytest.fixture(scope="session")
@@ -176,10 +165,10 @@ def subscriber(
     job_e: Task[P, str],
     job_f: Task[P, str],
     job_g: Task[P, str],
-        job_h: Task[P, str],
-        job_i: Task[P, str],
-        job_l: Task[P, str],
-        job_m: Task[P, str],
+    job_h: Task[P, str],
+    job_i: Task[P, str],
+    job_l: Task[P, str],
+    job_m: Task[P, str],
 ) -> None:
     subscribe("index.high", job_a)
     subscribe("index.low", job_b)