opendp · cbaycity · Oct 6, 2025 · Oct 4, 2025 · Oct 5, 2025
diff --git a/.ci/common.yml b/.ci/common.yml
@@ -10,7 +10,7 @@ variables:
   FF_USE_FASTZIP: "true"
 
 .base:
-  image: registry.gitlab.com/tumult-labs/ops/ci/linux:python3.9
+  image: registry.gitlab.com/tumult-labs/ops/ci/linux:python3.10
   before_script:
     - java -version
     - python --version

diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
@@ -82,7 +82,7 @@ jobs:
         # Note: mac runners are rather expensive (10x multiplier) so we don't use them here.
         os: [ubuntu-latest]
         dependencies: [oldest, newest]
-        python: ["3.9", "3.12"]
+        python: ["3.10", "3.12"]
     runs-on: ${{ matrix.os }}
     needs: Package
     steps:

diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
@@ -37,7 +37,7 @@ package:
   extends: .base
   stage: setup
   needs: []
-  image: registry.gitlab.com/tumult-labs/ops/ci/linux:python3.9
+  image: registry.gitlab.com/tumult-labs/ops/ci/linux:python3.10
   script:
     - nox -s build
   artifacts:
@@ -134,9 +134,9 @@ test_dep_matrix:
   needs: ["package"]
   parallel:
     matrix:
-      - PYTHON_VERSION: ["3.9", "3.10", "3.11", "3.12"]
+      - PYTHON_VERSION: ["3.10", "3.11", "3.12"]
         TEST_TYPE: ["oldest", "newest"]
-      - PYTHON_VERSION: ["3.9"]
+      - PYTHON_VERSION: ["3.10"]
         TEST_TYPE: ["pyspark3.4"]
   image: registry.gitlab.com/tumult-labs/ops/ci/linux:python${PYTHON_VERSION}
   rules:
@@ -182,7 +182,7 @@ benchmark_dependency_matrix:
   needs: ["package"]
   parallel:
     matrix:
-      - PYTHON_VERSION: ["3.9", "3.10", "3.11", "3.12"]
+      - PYTHON_VERSION: ["3.10", "3.11", "3.12"]
         TEST_TYPE: ["oldest", "newest"]
   image: registry.gitlab.com/tumult-labs/ops/ci/linux:python${PYTHON_VERSION}
   script:
@@ -205,7 +205,7 @@ test_release_linux:
   needs: ["package"]
   parallel:
     matrix: # 3.10, 3.11, and 3.12 run out of memory on a c6a.xlarge.
-      - PYTHON_VERSION: ["3.9"]
+      - PYTHON_VERSION: ["3.10"]
         INSTANCE: aws-c6a.xlarge
       - PYTHON_VERSION: ["3.10", "3.11", "3.12"]
         INSTANCE: aws-m6a.2xlarge
@@ -236,7 +236,7 @@ audit:
   needs: ["package"]
   parallel:
     matrix:
-      - PYTHON_VERSION: ["3.9", "3.10", "3.11", "3.12"]
+      - PYTHON_VERSION: ["3.10", "3.11", "3.12"]
   image: registry.gitlab.com/tumult-labs/ops/ci/linux:python${PYTHON_VERSION}
   script:
     - nox -s "audit(python=\"${PYTHON_VERSION}\")"

diff --git a/.python-version b/.python-version
@@ -1 +1 @@
-3.9
+3.10
diff --git a/CHANGELOG.rst b/CHANGELOG.rst
@@ -12,6 +12,7 @@ Unreleased
 
 Changed
 ~~~~~~~
+- Dropped support for Python 3.9, as it has reached end-of-life.
 - Dropped support for pyspark <3.5.0 on Macs after discovering that these configurations frequently crash. Older versions of the library may also be affected.
 
 .. _v0.20.2:

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
@@ -19,7 +19,7 @@ Once you have agreement on the feature or bug, anyone can send us a Pull Request
 
 We use [`uv`](https://docs.astral.sh/uv/) for dependency management during development. To set up your environment, install `uv` by following its [installation instructions](https://docs.astral.sh/uv/getting-started/installation/), then install the prerequisites listed in the [Tumult Analytics installation instructions](https://opendp.github.io/tumult-docs/analytics/latest/installation.html#prerequisites), and finally install our dev dependencies by running `uv sync` from the root of this repository.
 
-To minimize compatibility issues, doing development on the oldest supported Python minor version (currently 3.9) is strongly recommended.
+To minimize compatibility issues, doing development on the oldest supported Python minor version (currently 3.10) is strongly recommended.
 If you are using `uv` to manage your Python installations, running `uv sync` without an existing virtual environment should automatically install and use an appropriate Python version.
 
 ### Basic usage

diff --git a/doc/installation.rst b/doc/installation.rst
@@ -12,7 +12,7 @@ Prerequisites
 ^^^^^^^^^^^^^
 
 |project| is built in `Python <https://www.python.org/>`__, so a Python installation is required to use it.
-It is compatible with Python 3.9 through 3.11, and has experimental support for Python 3.12.
+It is compatible with Python 3.10 through 3.11, and has experimental support for Python 3.12.
 Because Tumult Analytics uses PySpark for computation, it also `requires Java 8 or 11 <https://archive.apache.org/dist/spark/docs/3.1.1/#downloading>`__, or Java 17 if PySpark 3.4 or later is used.
 Java 21 is not currently supported.
 

diff --git a/noxfile.py b/noxfile.py
@@ -36,26 +36,6 @@ def is_mac():
 
 
 DEPENDENCY_MATRIX = [
-    DependencyConfiguration(
-        id="3.9-oldest",
-        python="3.9",
-        packages={
-            "pyspark[sql]": "==3.3.1" if not is_mac() else "==3.5.0",
-            "sympy": "==1.8",
-            "pandas": "==1.4.0",
-            "tmlt.core": "==0.18.0",
-        },
-    ),
-    DependencyConfiguration(
-        id="3.9-newest",
-        python="3.9",
-        packages={
-            "pyspark[sql]": "==3.5.6",
-            "sympy": "==1.9",
-            "pandas": "==1.5.3",
-            "tmlt.core": ">=0.18.0",
-        },
-    ),
     DependencyConfiguration(
         id="3.10-oldest",
         python="3.10",
@@ -118,7 +98,7 @@ def is_mac():
     ),
 ]
 
-AUDIT_VERSIONS = ["3.9", "3.10", "3.11", "3.12"]
+AUDIT_VERSIONS = ["3.10", "3.11", "3.12"]
 AUDIT_SUPPRESSIONS = [
     "PYSEC-2023-228",
     # Affects: pip<23.3
@@ -151,6 +131,7 @@ def is_mac():
     package=PACKAGE_NAME,
     package_github=PACKAGE_GITHUB,
     directory=CWD,
+    default_python_version="3.10",
     smoketest_script=SMOKETEST_SCRIPT,
     parallel_tests=False,
     min_coverage=MIN_COVERAGE,

diff --git a/pyproject.toml b/pyproject.toml
@@ -18,7 +18,6 @@ classifiers = [
   "Topic :: Security",
 
   "Programming Language :: Python :: 3",
-  "Programming Language :: Python :: 3.9",
   "Programming Language :: Python :: 3.10",
   "Programming Language :: Python :: 3.11",
   "Programming Language :: Python :: 3.12",
@@ -27,7 +26,7 @@ keywords = [
   "differential privacy",
 ]
 
-requires-python = ">=3.9,<3.13"
+requires-python = ">=3.10,<3.13"
 dependencies = [
     # When updating Core, PySpark, Pandas, or SymPy, remember to update the
     # dependency matrix in the noxfile.
-Original file line number
+Diff line change
@@ Expand Up / @@ -12,6 +12,7 @@ Unreleased @@
     Changed
     ~~~~~~~
+    - Dropped support for Python 3.9, as it has reached end-of-life.
     - Dropped support for pyspark <3.5.0 on Macs after discovering that these configurations frequently crash. Older versions of the library may also be affected.
     .. _v0.20.2:
@@ Expand Down @@