Remove support for Python 3.9 (EOL)

.github/workflows/run-test-suite.yml

@@ -21,7 +21,7 @@ jobs:
       matrix:
         os: [ubuntu-latest, ubuntu-18.04, macos-latest, macos-10.15]
         # Note: keep versions quoted as strings else 3.10 taken as 3.1, etc.
-        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
+        python-version: ["3.10", "3.11", "3.12", "3.13"]
 
     # Run on new and old(er) versions of the distros we support (Linux, Mac OS)
     runs-on: ${{ matrix.os }}
@@ -95,7 +95,7 @@ jobs:
 
     # For one job only, generate a coverage report:
     - name: Upload coverage report to Codecov
-      # Get coverage from only one job (choose with Ubuntu Python 3.9 as
+      # Get coverage from only one job (choose with Ubuntu Python 3.10 as
       # representative). Note that we could use a separate workflow
       # to setup Codecov reports, but given the amount of steps required to
       # install including dependencies via conda, that a separate workflow
@@ -104,7 +104,7 @@ jobs:
       # passing at least for that job, avoiding useless coverage reports.
       uses: codecov/codecov-action@v1
       if: |
-        matrix.os == "ubuntu-latest" && matrix.python-version == "3.9"
+        matrix.os == "ubuntu-latest" && matrix.python-version == "3.10"
       with:
         file: ./cfdm/test/cfdm_coverage_reports/coverage.xml
         fail_ci_if_error: true

Changelog.rst

@@ -3,11 +3,14 @@ Version NEXTVERSION
 
 **2025-10-??**
 
+* Python 3.9 support removed
+  (https://github.com/NCAS-CMS/cfdm/issues/353)
 * When changing array data type, retain cached data elements cast to
   the new type (https://github.com/NCAS-CMS/cfdm/issues/358)
 * Fix bug that prevented `cfdm.read` from reading a file with ``#``
   characters in its file name
   (https://github.com/NCAS-CMS/cfdm/issues/356)
+* Changed dependency: ``Python>=3.10.0``
 
 ----
 

cfdm/core/__init__.py

@@ -35,7 +35,7 @@
         )
 
 # Check the version of python
-_minimum_vn = "3.9.0"
+_minimum_vn = "3.10.0"
 if Version(python_version()) < Version(_minimum_vn):
     raise ValueError(
         f"Bad python version: cfdm.core requires python>={_minimum_vn}. "

cfdm/test/test_Data.py

@@ -1377,7 +1377,9 @@ def test_Data_masked_values(self):
         d = cfdm.Data(array)
         e = d.masked_values(1.1)
         ea = e.array
-        a = np.ma.masked_values(array, 1.1, rtol=cfdm.rtol(), atol=cfdm.atol())
+        a = np.ma.masked_values(
+            array, 1.1, rtol=float(cfdm.rtol()), atol=float(cfdm.atol())
+        )
         self.assertTrue(np.isclose(ea, a).all())
         self.assertTrue((ea.mask == a.mask).all())
         self.assertIsNone(d.masked_values(1.1, inplace=True))

docs/source/installation.rst

@@ -29,7 +29,7 @@ cfdm works for Linux, Mac and Windows operating systems.
 **Python versions**
 -------------------
 
-cfdm works for Python versions 3.9 or newer.
+cfdm works for Python versions 3.10 or newer.
 
 ----
 
@@ -180,7 +180,7 @@ Tests are run from within the ``cfdm/test`` directory:
 
 The cfdm package requires:
 
-* `Python <https://www.python.org>`_, version 3.9 or newer.
+* `Python <https://www.python.org>`_, version 3.10 or newer.
 
 * `numpy <http://www.numpy.org>`_, version 2.0.0 or newer.
 

setup.py

@@ -169,15 +169,14 @@ def _get_version():
         "Operating System :: OS Independent",
         "Programming Language :: Python",
         "Programming Language :: Python :: 3",
-        "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",
     ],
     packages=find_packages(),
     scripts=["scripts/cfdump"],
-    python_requires=">=3.9",
+    python_requires=">=3.10",
     install_requires=install_requires,
     tests_require=tests_require,
     extras_require=extras_require,