diff --git a/.github/workflows/ci-tests.yml b/.github/workflows/ci-tests.yml
index 691a145..152b8fe 100644
--- a/.github/workflows/ci-tests.yml
+++ b/.github/workflows/ci-tests.yml
@@ -18,10 +18,11 @@ jobs:
     runs-on: ubuntu-20.04  # 22.04 doesn't support Python 3.6
 
     strategy:
+      fail-fast: false
       matrix:
         # The README.rst file mentions the versions tested, please update it as well
         py-ver-major: [3]
-        py-ver-minor: [8, 9, 10, 11, 12]
+        py-ver-minor: [8, 9, 10, 11, 12, 13]
         step: [lint, unit, mypy, bandit]
 
     env:
@@ -37,6 +38,7 @@ jobs:
         uses: actions/setup-python@v5
         with:
           python-version: ${{ env.py-semver }}
+          allow-prereleases: true
           cache: pip
           cache-dependency-path: |
             requirements.txt
diff --git a/README.rst b/README.rst
index c4c50dd..d1cc50e 100644
--- a/README.rst
+++ b/README.rst
@@ -32,7 +32,7 @@ This is a testing tool for checking the output of Tools and Workflows described
 with the Common Workflow Language.  Among other uses, it is used to run the CWL
 conformance tests.
 
-This is written and tested for Python 3.8, 3.9, 3.10, 3.11, and 3.12.
+This is written and tested for Python 3.8, 3.9, 3.10, 3.11, 3.12, and 3.13.
 
 .. contents:: Table of Contents
    :local:
diff --git a/pyproject.toml b/pyproject.toml
index ddc54be..8daf19f 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -22,9 +22,10 @@ classifiers = [
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",
+    "Programming Language :: Python :: 3.13",
     "Typing :: Typed",
 ]
-requires-python = ">=3.8,<3.13"
+requires-python = ">=3.8,<3.14"
 dynamic = ["version", "dependencies"]
 
 [project.readme]
diff --git a/tox.ini b/tox.ini
index f036283..93aadfa 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,9 +1,9 @@
 [tox]
 envlist =
-  py3{8,9,10,11,12}-lint,
-  py3{8,9,10,11,12}-unit,
-  py3{8,9,10,11,12}-bandit,
-  py3{8,9,10,11,12}-mypy,
+  py3{8,9,10,11,12,13}-lint,
+  py3{8,9,10,11,12,13}-unit,
+  py3{8,9,10,11,12,13}-bandit,
+  py3{8,9,10,11,12,13}-mypy,
   py312-lintreadme,
   py312-pydocstyle
 
@@ -22,16 +22,17 @@ python =
   3.10: py310
   3.11: py311
   3.12: py312
+  3.13: py313
 
 [testenv]
 skipsdist =
-  py3{8,9,10,11,12}-!{unit,mypy,lintreadme} = True
+  py3{8,9,10,11,12,13}-!{unit,mypy,lintreadme} = True
 
 description =
-  py3{8,9,10,11,12}-unit: Run the unit tests
-  py3{8,9,10,11,12}-lint: Lint the Python code
-  py3{8,9,10,11,12}-bandit: Search for common security issues
-  py3{8,9,10,11,12}-mypy: Check for type safety
+  py3{8,9,10,11,12,13}-unit: Run the unit tests
+  py3{8,9,10,11,12,13}-lint: Lint the Python code
+  py3{8,9,10,11,12,13}-bandit: Search for common security issues
+  py3{8,9,10,11,12,13}-mypy: Check for type safety
   py312-pydocstyle: docstring style checker
   py312-lintreadme: Lint the README.rst->.md conversion
 
@@ -40,36 +41,36 @@ passenv =
   GITHUB_*
 
 deps =
-  py3{8,9,10,11,12}-{unit,mypy}: -rrequirements.txt
-  py3{8,9,10,11,12}-{unit,mypy}: -rtest-requirements.txt
-  py3{8,9,10,11,12}-lint: flake8-bugbear
-  py3{8,9,10,11,12}-lint: black~=23.1
-  py3{8,9,10,11,12}-bandit: bandit
-  py3{8,9,10,11,12}-mypy: -rmypy-requirements.txt
+  py3{8,9,10,11,12,13}-{unit,mypy}: -rrequirements.txt
+  py3{8,9,10,11,12,13}-{unit,mypy}: -rtest-requirements.txt
+  py3{8,9,10,11,12,13}-lint: flake8-bugbear
+  py3{8,9,10,11,12,13}-lint: black~=23.1
+  py3{8,9,10,11,12,13}-bandit: bandit
+  py3{8,9,10,11,12,13}-mypy: -rmypy-requirements.txt
 
 set_env =
-  py3{8,3,10,11,12}-unit: LC_ALL = C.UTF-8
+  py3{8,3,10,11,12,13}-unit: LC_ALL = C.UTF-8
   COV_CORE_SOURCE=cwltest
   COV_CORE_CONFIG={toxinidir}/.coveragerc
   COV_CORE_DATAFILE={toxinidir}/.coverage.eager
 
 commands =
-  py3{8,9,10,11,12}-unit: python -m pip install -U pip setuptools wheel
-  py3{8,9,10,11,12}-unit: python -m pytest --cov --cov-config={toxinidir}/.coveragerc --cov-append {posargs}
-  py3{8,9,10,11,12}-unit: coverage xml
-  py3{8,9,10,11,12}-bandit: bandit --recursive cwltest
-  py3{8,9,10,11,12}-lint: make flake8
-  py3{8,9,10,11,12}-lint: make format-check
-  py3{8,9,10,11,12}-mypy: make mypy
+  py3{8,9,10,11,12,13}-unit: python -m pip install -U pip setuptools wheel
+  py3{8,9,10,11,12,13}-unit: python -m pytest --cov --cov-config={toxinidir}/.coveragerc --cov-append {posargs}
+  py3{8,9,10,11,12,13}-unit: coverage xml
+  py3{8,9,10,11,12,13}-bandit: bandit --recursive cwltest
+  py3{8,9,10,11,12,13}-lint: make flake8
+  py3{8,9,10,11,12,13}-lint: make format-check
+  py3{8,9,10,11,12,13}-mypy: make mypy
 
 allowlist_externals =
-  py3{8,9,10,11,12}-lint: flake8
-  py3{8,9,10,11,12}-lint: black
-  py3{8,9,10,11,12}-{mypy,shellcheck,lint,unit}: make
+  py3{8,9,10,11,12,13}-lint: flake8
+  py3{8,9,10,11,12,13}-lint: black
+  py3{8,9,10,11,12,13}-{mypy,shellcheck,lint,unit}: make
 
 skip_install =
-  py3{8,9,10,11,12}-lint: true
-  py3{8,9,10,11,12}-bandit: true
+  py3{8,9,10,11,12,13}-lint: true
+  py3{8,9,10,11,12,13}-bandit: true
 
 
 [testenv:py312-pydocstyle]