diff --git a/dials_data/download.py b/dials_data/download.py
index 15798e61..9b205a23 100644
--- a/dials_data/download.py
+++ b/dials_data/download.py
@@ -7,13 +7,11 @@
 import hashlib
 import os
 import tarfile
-import warnings
 import zipfile
 from pathlib import Path
 from typing import Any
 from urllib.parse import urlparse
 
-import py.path
 import requests
 from requests.adapters import HTTPAdapter
 from urllib3.util.retry import Retry
@@ -300,36 +298,25 @@ def result_filter(self, result, **kwargs):
         """
         return result
 
-    def __call__(self, test_data: str, pathlib=None, **kwargs):
+    def __call__(self, test_data: str, **kwargs):
         """
         Return the location of a dataset, transparently downloading it if
         necessary and possible.
         The return value can be manipulated by overriding the result_filter
         function.
         :param test_data: name of the requested dataset.
-        :param pathlib: Whether to return the result as a Python pathlib object.
-                        The default for this setting is 'False' for now (leading
-                        to a py.path.local object being returned), but the default
-                        will change to 'True' in a future dials.data release.
-                        Set to 'True' for forward compatibility.
         :return: A pathlib or py.path.local object pointing to the dataset, or False
                  if the dataset is not available.
         """
+        if "pathlib" in kwargs:
+            raise ValueError(
+                "The pathlib parameter has been removed. The "
+                "DataFetcher always returns pathlib.Path() objects now."
+            )
         if test_data not in self._cache:
             self._cache[test_data] = self._attempt_fetch(test_data)
-        if pathlib is None:
-            warnings.warn(
-                "The DataFetcher currently returns py.path.local() objects. "
-                "This will in the future change to pathlib.Path() objects. "
-                "You can either add a pathlib=True argument to obtain a pathlib.Path() object, "
-                "or pathlib=False to silence this warning for now.",
-                DeprecationWarning,
-                stacklevel=2,
-            )
         if not self._cache[test_data]:
             return self.result_filter(result=False)
-        elif not pathlib:
-            return self.result_filter(result=py.path.local(self._cache[test_data]))
         return self.result_filter(result=self._cache[test_data])
 
     def _attempt_fetch(self, test_data: str) -> Path | None:
diff --git a/pyproject.toml b/pyproject.toml
index dec8455b..cb0bf15f 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,10 +4,10 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "dials_data"
-version = "2.4.0"
+version = "3.0.0"
 description = "DIALS Regression Data Manager"
 authors = [
-    { name = "DIALS development team", email = "dials-support@lists.sourceforge.net" },
+    { name = "DIALS development team", email = "dials-user-group@jiscmail.ac.uk" },
 ]
 license = { text = "BSD 3-Clause License" }
 classifiers = [
diff --git a/tests/test_dials_data.py b/tests/test_dials_data.py
index f9a203ed..c33b3fd4 100644
--- a/tests/test_dials_data.py
+++ b/tests/test_dials_data.py
@@ -1,11 +1,7 @@
 from __future__ import annotations
 
-import pathlib
 from unittest import mock
 
-import py
-import pytest
-
 import dials_data
 import dials_data.datasets
 import dials_data.download
@@ -22,60 +18,12 @@ def test_repository_location():
 
 def test_fetching_undefined_datasets_does_not_crash():
     df = dials_data.download.DataFetcher(read_only=True)
-    assert df("aardvark", pathlib=True) is False
+    assert df("aardvark") is False
 
 
 def test_requests_for_future_datasets_can_be_intercepted():
     df = dials_data.download.DataFetcher(read_only=True)
     df.result_filter = mock.Mock()
     df.result_filter.return_value = False
-    assert df("aardvark", pathlib=True) is False
+    assert df("aardvark") is False
     df.result_filter.assert_called_once_with(result=False)
-
-
-@mock.patch("dials_data.datasets.repository_location")
-@mock.patch("dials_data.download.fetch_dataset")
-def test_datafetcher_constructs_py_path(fetcher, root):
-    root.return_value = pathlib.Path("/tmp/root")
-    fetcher.return_value = True
-
-    df = dials_data.download.DataFetcher(read_only=True)
-    with pytest.warns(DeprecationWarning):
-        ds = df("dataset")
-    assert pathlib.Path(ds).resolve() == pathlib.Path("/tmp/root/dataset").resolve()
-    assert isinstance(ds, py.path.local)
-    fetcher.assert_called_once_with(
-        "dataset", pre_scan=True, read_only=False, verify=True
-    )
-
-    ds = df("dataset", pathlib=False)
-    assert pathlib.Path(ds).resolve() == pathlib.Path("/tmp/root/dataset").resolve()
-    assert isinstance(ds, py.path.local)
-    fetcher.assert_called_once()
-
-
-@mock.patch("dials_data.datasets.repository_location")
-@mock.patch("dials_data.download.fetch_dataset")
-def test_datafetcher_constructs_path(fetcher, root):
-    test_path = pathlib.Path("/tmp/root")
-    root.return_value = test_path
-    fetcher.return_value = True
-
-    df = dials_data.download.DataFetcher(read_only=True)
-    ds = df("dataset", pathlib=True)
-    assert ds == test_path / "dataset"
-
-    assert isinstance(ds, pathlib.Path)
-    fetcher.assert_called_once_with(
-        "dataset", pre_scan=True, read_only=False, verify=True
-    )
-
-    with pytest.warns(DeprecationWarning):
-        ds = df("dataset")
-    assert pathlib.Path(ds).resolve() == test_path.joinpath("dataset").resolve()
-    assert not isinstance(
-        ds, pathlib.Path
-    )  # default is currently to return py.path.local()
-    fetcher.assert_called_once_with(
-        "dataset", pre_scan=True, read_only=False, verify=True
-    )