diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index b96497e..59b5589 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -10,7 +10,7 @@ on:
 
 jobs:
   test:
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-24.04
     strategy:
       fail-fast: false
       matrix:
@@ -21,11 +21,17 @@ jobs:
             plone: 5.2
           - python: 3.10.11
             plone: "6.0"
+          - python: 3.13.1
+            plone: "6.1"
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
+      - name: Install dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y libjpeg62 libjpeg62-dev libbz2-dev
       - name: Set up pyenv and Python
-        uses: "gabrielfalcao/pyenv-action@v14"
+        uses: "gabrielfalcao/pyenv-action@v18"
         with:
           default: "${{ matrix.python }}"
       - name: Setup Env
@@ -38,8 +44,7 @@ jobs:
           cache-name: cache-eggs
         with:
           path: ~/buildout-cache/eggs
-          key: ${{ runner.os }}-test-${{ env.cache-name }}-${{ matrix.plone }}
-          restore-keys: ${{ runner.os }}-test-${{ env.cache-name }}-${{ matrix.plone }}
+          key: ${{ runner.os }}-test-${{ env.cache-name }}-${{ matrix.python }}-${{ matrix.plone }}
       - name: buildout
         run: |
           sed -ie "s#test.cfg#test-${{matrix.plone}}.cfg#" gha.cfg
@@ -49,18 +54,18 @@ jobs:
         run: |
           bin/test -t !robot
   coverage:
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-24.04
     strategy:
       fail-fast: false
       matrix:
         include:
-          - python: 3.10.11
-            plone: "6.0"
+          - python: 3.13.1
+            plone: "6.1"
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Set up pyenv and Python
-        uses: "gabrielfalcao/pyenv-action@v14"
+        uses: "gabrielfalcao/pyenv-action@v18"
         with:
           default: "${{ matrix.python }}"
       - name: Setup Env
@@ -74,8 +79,7 @@ jobs:
           cache-name: cache-eggs
         with:
           path: ~/buildout-cache/eggs
-          key: ${{ runner.os }}-test-${{ env.cache-name }}-${{ matrix.plone }}
-          restore-keys: ${{ runner.os }}-test-${{ env.cache-name }}-${{ matrix.plone }}
+          key: ${{ runner.os }}-test-${{ env.cache-name }}-${{ matrix.python }}-${{ matrix.plone }}
       - name: buildout
         run: |
           sed -ie "s#test.cfg#test-${{matrix.plone}}.cfg#" gha.cfg
diff --git a/.gitignore b/.gitignore
index fa70860..465dada 100644
--- a/.gitignore
+++ b/.gitignore
@@ -12,6 +12,7 @@
 # dirs
 bin/
 buildout-cache/
+CACHEDIR.TAG
 checkversion*.html
 develop-eggs/
 eggs/
diff --git a/CHANGES.rst b/CHANGES.rst
index 4b88a0a..f6be50b 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -5,7 +5,8 @@ Changelog
 0.5 (unreleased)
 ----------------
 
-- Nothing changed yet.
+- Added Plone 6.1 version in buildout.
+  [chris-adam]
 
 
 0.4 (2024-06-07)
diff --git a/Makefile b/Makefile
index 1b1c128..83b67ac 100644
--- a/Makefile
+++ b/Makefile
@@ -1,10 +1,10 @@
 #!/usr/bin/make
-# pyenv is a requirement, with 2.7, 3.7 and 3.10 python versions, and virtualenv installed in each version
+# pyenv is a requirement, with 2.7, 3.7, 3.10 and 3.13 python versions, and virtualenv installed in each version
 # plone parameter must be passed to create environment 'make setup plone=6.0' or after a make cleanall
 # The original Makefile can be found on https://github.com/IMIO/scripts-buildout
 
 SHELL=/bin/bash
-plones=4.3 5.2 6.0
+plones=4.3 5.2 6.0 6.1
 b_o=
 old_plone=$(shell [ -e .plone-version ] && cat .plone-version)
 
@@ -15,10 +15,13 @@ endif
 ifndef plone
 ifeq (,$(filter setup,$(MAKECMDGOALS)))
   plone=$(old_plone)
-  b_o=-N
 endif
 endif
 
+ifneq ($(wildcard bin/instance),)
+    b_o=-N
+endif
+
 ifndef python
 ifeq ($(plone),4.3)
   python=2.7
@@ -29,6 +32,9 @@ endif
 ifeq ($(plone),6.0)
   python=3.10
 endif
+ifeq ($(plone),6.1)
+  python=3.13
+endif
 endif
 
 all: buildout
diff --git a/requirements-4.3.txt b/requirements-4.3.txt
index 1bc2650..14b7bdc 100644
--- a/requirements-4.3.txt
+++ b/requirements-4.3.txt
@@ -1,4 +1,4 @@
 pip==20.3.4
 setuptools==44.1.1
-zc.buildout==2.13.3
+zc.buildout==3.1.1
 wheel==0.37.1
diff --git a/requirements-6.1.txt b/requirements-6.1.txt
new file mode 100644
index 0000000..aaf0495
--- /dev/null
+++ b/requirements-6.1.txt
@@ -0,0 +1,3 @@
+-c https://dist.plone.org/release/6.1-latest/requirements.txt
+setuptools
+zc.buildout
diff --git a/setup.py b/setup.py
index 3615425..8da4aff 100644
--- a/setup.py
+++ b/setup.py
@@ -5,16 +5,18 @@
 from setuptools import setup
 
 
-long_description = '\n\n'.join([
-    open('README.rst').read(),
-    open('CONTRIBUTORS.rst').read(),
-    open('CHANGES.rst').read(),
-])
+long_description = "\n\n".join(
+    [
+        open("README.rst").read(),
+        open("CONTRIBUTORS.rst").read(),
+        open("CHANGES.rst").read(),
+    ]
+)
 
 
 setup(
-    name='collective.behavior.internalnumber',
-    version='0.5.dev0',
+    name="collective.behavior.internalnumber",
+    version="0.5.dev0",
     description="Configurable internal number plone behavior",
     long_description=long_description,
     # Get more from https://pypi.python.org/pypi?%3Aaction=list_classifiers
@@ -26,40 +28,42 @@
         "Framework :: Plone :: 4.3",
         "Framework :: Plone :: 5.2",
         "Framework :: Plone :: 6.0",
+        "Framework :: Plone :: 6.1",
         "Programming Language :: Python",
         "Programming Language :: Python :: 2.7",
         "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.10",
+        "Programming Language :: Python :: 3.13",
         "Operating System :: OS Independent",
         "License :: OSI Approved :: GNU General Public License v2 (GPLv2)",
     ],
-    keywords='Python Plone',
-    author='Stephan Geulette',
-    author_email='support@imio.be',
+    keywords="Python Plone",
+    author="Stephan Geulette",
+    author_email="support@imio.be",
     # url='https://pypi.python.org/pypi/collective.behavior.internalnumber',
     project_urls={
         "PyPI": "https://pypi.python.org/pypi/collective.behavior.internalnumber",
         "Source": "https://github.com/collective/collective.behavior.internalnumber",
     },
-    license='GPL version 2',
-    packages=find_packages('src', exclude=['ez_setup']),
-    namespace_packages=['collective', 'collective.behavior'],
-    package_dir={'': 'src'},
+    license="GPL version 2",
+    packages=find_packages("src", exclude=["ez_setup"]),
+    namespace_packages=["collective", "collective.behavior"],
+    package_dir={"": "src"},
     include_package_data=True,
     zip_safe=False,
     install_requires=[
-        'plone.api',
-        'Products.GenericSetup>=1.8.2',
-        'setuptools',
-        'collective.behavior.talcondition',
-        'collective.z3cform.datagridfield',
+        "plone.api",
+        "Products.GenericSetup>=1.8.2",
+        "setuptools",
+        "collective.behavior.talcondition",
+        "collective.z3cform.datagridfield",
     ],
     extras_require={
-        'test': [
-            'plone.app.testing',
-            'plone.testing>=5.0.0',
-            'plone.app.contenttypes',
-            'plone.app.robotframework[debug]',
+        "test": [
+            "plone.app.testing",
+            "plone.testing>=5.0.0",
+            "plone.app.contenttypes",
+            "plone.app.robotframework[debug]",
         ],
     },
     entry_points="""
diff --git a/test-6.1.cfg b/test-6.1.cfg
new file mode 100644
index 0000000..0578993
--- /dev/null
+++ b/test-6.1.cfg
@@ -0,0 +1,37 @@
+[buildout]
+
+extends =
+    https://raw.githubusercontent.com/collective/buildout.plonetest/master/test-6.1.x.cfg
+    base.cfg
+
+# update-versions-file = test-6.1.cfg
+
+[versions]
+# to keep prompt-toolkit < 3
+ipython = 8.3.0
+
+ipdb = 0.13.9
+iw.debug = 0.3
+jedi = 0.18.1
+parso = 0.8.3
+
+# Required by:
+# ipdb
+asttokens = 2.0.8
+backcall = 0.2.0
+executing = 1.1.1
+matplotlib-inline = 0.1.6
+pexpect = 4.8.0
+pickleshare = 0.7.5
+ptyprocess = 0.7.0
+pure-eval = 0.2.2
+stack-data = 0.5.1
+traitlets = 5.4.0
+
+# Required by:
+# collective.behavior.internalnumber==0.2.dev0
+collective.behavior.talcondition = 1.0a1
+
+# Required by:
+# collective.behavior.internalnumber==0.2.dev0
+collective.z3cform.datagridfield = 3.0.1