diff --git a/.github/workflows/benchmark.yaml b/.github/workflows/benchmark.yaml
index 0e6bd52b..ba1a6de3 100644
--- a/.github/workflows/benchmark.yaml
+++ b/.github/workflows/benchmark.yaml
@@ -39,7 +39,7 @@ jobs:
       - name: Setup Python
         uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6
         with:
-          python-version: "3.14"
+          python-version: "3.12"
 
       - name: Upgrade pip
         run: |
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index a41158dc..2fcbdceb 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -32,7 +32,7 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
         with:
-          python-version: "3.14"
+          python-version: "3.12"
 
       - name: Upgrade pip
         run: |
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index a937b22e..4a626356 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -23,17 +23,18 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - { python: "3.9", os: "ubuntu-latest", session: "tests" }
           - { python: "3.10", os: "ubuntu-latest", session: "tests" }
-          - { python: "3.11", os: "ubuntu-latest", session: "pre-commit" }
-          - { python: "3.11", os: "ubuntu-latest", session: "xdoctest" }
-          - { python: "3.11", os: "ubuntu-latest", session: "docs-build" }
           - { python: "3.11", os: "ubuntu-latest", session: "tests" }
-          - { python: "3.11", os: "windows-latest", session: "tests" }
-          - { python: "3.11", os: "ubuntu-latest", session: "pip-audit" }
+          - { python: "3.12", os: "ubuntu-latest", session: "pre-commit" }
+          - { python: "3.12", os: "ubuntu-latest", session: "xdoctest" }
+          - { python: "3.12", os: "ubuntu-latest", session: "docs-build" }
+          - { python: "3.12", os: "ubuntu-latest", session: "tests" }
+          - { python: "3.12", os: "windows-latest", session: "tests" }
+          - { python: "3.12", os: "ubuntu-latest", session: "pip-audit" }
+          - { python: "3.13", os: "ubuntu-latest", session: "tests" }
 
     #          - { python: "3.10", os: "ubuntu-latest", session: "mypy" }
-    #          - { python: "3.9", os: "ubuntu-latest", session: "mypy" }
+    #          - { python: "3.12", os: "ubuntu-latest", session: "mypy" }
     #          - { python: "3.10", os: "ubuntu-latest", session: "typeguard" }
 
     env:
@@ -141,7 +142,7 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
         with:
-          python-version: "3.14"
+          python-version: "3.12"
 
       - name: Upgrade pip
         run: |
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index c1f39fcc..23680c8e 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -41,7 +41,7 @@ repos:
       - id: pyupgrade
         description: Automatically upgrade syntax for newer versions.
         types: [python]
-        args: [--py37-plus]
+        args: [--py310-plus]
 
 # Prettier is failing in CI for Markdown files, so we disable it for now. It does not do much for us anyway.
 #  - repo: https://github.com/pre-commit/mirrors-prettier
diff --git a/.readthedocs.yml b/.readthedocs.yml
index 66f2a214..1121f1eb 100644
--- a/.readthedocs.yml
+++ b/.readthedocs.yml
@@ -2,7 +2,7 @@ version: 2
 build:
   os: ubuntu-20.04
   tools:
-    python: "3.10"
+    python: "3.12"
 sphinx:
   configuration: docs/conf.py
 formats: all
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 5f6f1a0c..ed030b80 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -46,7 +46,7 @@ Indicate you are working on a task by adding your GitHub @name after the task in
 Definition of Done items are often a great starting point for contributing in a meaningful way while getting integrated into team practices.
 Using SSH keys to check out the repository is ideal, as we require contributors to sign their commits.
 
-You need Python 3.9+ and the following tools:
+You need Python 3.10, 3.11, 3.12, or 3.13 and the following tools:
 
 - [uv]
 - [Nox]
diff --git a/README.md b/README.md
index 0be07a40..3b3e0d80 100644
--- a/README.md
+++ b/README.md
@@ -46,7 +46,7 @@ metric is reported in hours.
 
 ## Requirements
 
-- Python 3.9+
+- Python 3.10, 3.11, 3.12, or 3.13
 - uv (installation instructions provided [here](https://github.com/astral-sh/uv?tab=readme-ov-file#installation))
 - Supported OS: Windows 10, Windows 11, Linux, MacOS
 
diff --git a/docs/architectural_decision_records/007-python-for-app-fuctionality.md b/docs/architectural_decision_records/007-python-for-app-fuctionality.md
index 9386e7b1..a37c3097 100644
--- a/docs/architectural_decision_records/007-python-for-app-fuctionality.md
+++ b/docs/architectural_decision_records/007-python-for-app-fuctionality.md
@@ -15,7 +15,7 @@ Our project includes data analysis.
 ## Decision
 
 We will use Python for the main application functionality, Python for tests, and Poetry for build and dependency automation.
-We are supporting Python 3.9 and 3.10 in order to use modern type hinting.
+We are supporting Python 3.10, 3.11, 3.12, and 3.13 in order to use modern type hinting.
 
 ## Rationale
 
diff --git a/noxfile.py b/noxfile.py
index c52b9a32..4e399fc1 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -15,7 +15,7 @@
 PYPROJECT = nox.project.load_toml("pyproject.toml")
 
 package = "devops_deployment_metrics"
-python_versions = ["3.11", "3.9", "3.10"]
+python_versions = ["3.12", "3.10", "3.11", "3.13"]
 nox.needs_version = ">= 2024.4.15"
 nox.options.sessions = (
     "pre-commit",
diff --git a/pyproject.toml b/pyproject.toml
index 3c36128c..3d56c9b7 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -3,10 +3,17 @@ name = "devops-deployment-metrics"
 version = "0.0.1"
 description = "DevOps Deployment Metrics"
 authors = [{ name = "Flexion, Inc.", email = "noreply@flexion.us" }]
-requires-python = "~=3.9"
+requires-python = ">=3.10"
 readme = "README.md"
 license = "MIT"
-classifiers = ["Development Status :: 1 - Planning"]
+classifiers = [
+    "Development Status :: 1 - Planning",
+    "Programming Language :: Python :: 3",
+    "Programming Language :: Python :: 3.10",
+    "Programming Language :: Python :: 3.11",
+    "Programming Language :: Python :: 3.12",
+    "Programming Language :: Python :: 3.13",
+]
 dependencies = [
     "click>=8.0.1",
     "pandas>=2.0.0,<3",
@@ -110,8 +117,8 @@ exclude = [
 line-length = 88
 indent-width = 4
 
-# Assume Python 3.8
-target-version = "py38"
+# Assume Python 3.12
+target-version = "py312"
 
 [tool.ruff.lint]
 # Enable Pyflakes (`F`)
diff --git a/src/devops_deployment_metrics/config.py b/src/devops_deployment_metrics/config.py
index 4c2f7dbf..ec0f1b8f 100644
--- a/src/devops_deployment_metrics/config.py
+++ b/src/devops_deployment_metrics/config.py
@@ -3,9 +3,9 @@
 from dataclasses import dataclass
 from datetime import datetime
 from pathlib import Path
+from zoneinfo import ZoneInfo
 
 import toml
-from zoneinfo import ZoneInfo
 
 from devops_deployment_metrics.workflow import Workflow
 
diff --git a/src/devops_deployment_metrics/metrics.py b/src/devops_deployment_metrics/metrics.py
index faeb667a..67fa1bcc 100644
--- a/src/devops_deployment_metrics/metrics.py
+++ b/src/devops_deployment_metrics/metrics.py
@@ -1,8 +1,9 @@
 """This module contains classes for calculating deployment metrics."""
 
+from collections.abc import Iterable
 from dataclasses import asdict
 from datetime import datetime, timedelta, timezone
-from typing import Any, Iterable, Optional
+from typing import Any
 
 import pandas as pd
 
@@ -45,7 +46,7 @@ def get_deployments_in_period(
         deployments: list[WorkflowRun],
         days_slice: int,
         start_date: datetime,
-        end_period: Optional[datetime] = None,
+        end_period: datetime | None = None,
     ) -> Iterable[tuple[datetime, list[WorkflowRun]]]:
         """Get the deployments for each period."""
         # Using this workaround to get the current datetime with the local timezone