diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 276708b..76473f7 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -9,14 +9,14 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest]
-        python-version: [2.7, 3.5, 3.6, 3.7, 3.8]
+        python-version: ["3.7", "3.8", "3.9", "3.10", "3.11", "3.12"]
 
     runs-on: ${{ matrix.os }}
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
 
     - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v1
+      uses: actions/setup-python@v4
       with:
         python-version: ${{ matrix.python-version }}
 
@@ -28,12 +28,12 @@ jobs:
   docs:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
 
-      - name: Set up Python 3.8
-        uses: actions/setup-python@v1
+      - name: Set up Python 3.11
+        uses: actions/setup-python@v4
         with:
-          python-version: 3.8
+          python-version: 3.11
 
       - name: Run sphinx
         run: |
@@ -43,12 +43,12 @@ jobs:
   linkcheck:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
 
-      - name: Set up Python 3.8
-        uses: actions/setup-python@v1
+      - name: Set up Python 3.11
+        uses: actions/setup-python@v4
         with:
-          python-version: 3.8
+          python-version: 3.11
 
       - name: Run sphinx
         run: |
diff --git a/CHANGES.rst b/CHANGES.rst
index c9843c9..31a04e7 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -1,3 +1,10 @@
+2.0 (unreleased)
+````````````````
+
+- Drop support for Python 2.7, 3.5, 3.6.
+- Add support for Python 3.9, 3.10, 3.11, 3.12.
+
+
 1.6.0 (2020-04-17)
 ``````````````````
 
diff --git a/docs/conf.py b/docs/conf.py
index 43ae451..ac46088 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -13,8 +13,8 @@
 exclude_patterns = ['_build']
 pygments_style = 'sphinx'
 extlinks = {
-    'issue': ('https://github.com/ikalnytskyi/sphinxcontrib-redoc/issues/%s', '#'),
-    'pr': ('https://github.com/ikalnytskyi/sphinxcontrib-redoc/pull/%s', 'PR #'),
+    'issue': ('https://github.com/ikalnytskyi/sphinxcontrib-redoc/issues/%s', '#%s'),
+    'pr': ('https://github.com/ikalnytskyi/sphinxcontrib-redoc/pull/%s', 'PR #%s'),
 }
 redoc = [
     {
diff --git a/setup.py b/setup.py
index 1c177b7..b2de312 100644
--- a/setup.py
+++ b/setup.py
@@ -30,7 +30,6 @@
         'jinja2 >= 2.4',
         'jsonschema >= 3.0',
         'sphinx >= 1.5',
-        'six >= 1.5',
         'PyYAML >= 3.12',
     ],
     classifiers=[
@@ -40,13 +39,13 @@
         'Intended Audience :: Developers',
         'Operating System :: OS Independent',
         'Programming Language :: Python',
-        'Programming Language :: Python :: 2',
-        'Programming Language :: Python :: 2.7',
         'Programming Language :: Python :: 3',
-        'Programming Language :: Python :: 3.5',
-        'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',
         'Programming Language :: Python :: 3.8',
+        'Programming Language :: Python :: 3.9',
+        'Programming Language :: Python :: 3.10',
+        'Programming Language :: Python :: 3.11',
+        'Programming Language :: Python :: 3.12',
     ],
     namespace_packages=['sphinxcontrib'],
 )
diff --git a/sphinxcontrib/redoc.py b/sphinxcontrib/redoc.py
index 6e1c194..78308c7 100644
--- a/sphinxcontrib/redoc.py
+++ b/sphinxcontrib/redoc.py
@@ -9,16 +9,15 @@
     :license: BSD, see LICENSE for details.
 """
 
-import io
 import os
 import json
+import urllib
 
 import jinja2
 import jsonschema
 import pkg_resources
 import yaml
 
-from six.moves import urllib
 from sphinx.util.fileutil import copy_asset
 from sphinx.util.osutil import copyfile, ensuredir
 
@@ -69,8 +68,8 @@ def render(app):
         jsonschema.validate(app.config.redoc, schema=_REDOC_CONF_SCHEMA)
     except jsonschema.ValidationError as exc:
         raise ValueError(
-            'Improper configuration for sphinxcontrib-redoc at %s: %s' % (
-                '.'.join((str(part) for part in exc.path)),
+            'Improper configuration for sphinxcontrib-redoc at {}: {}'.format(
+                '.'.join(str(part) for part in exc.path),
                 exc.message,
             )
         )
@@ -81,7 +80,7 @@ def render(app):
         else:
             template_path = os.path.join(_HERE, 'redoc.j2')
 
-        with io.open(template_path, encoding='utf-8') as f:
+        with open(template_path, encoding='utf-8') as f:
             template = jinja2.Template(f.read())
 
         # In embed mode, we are going to embed the whole OpenAPI spec into
@@ -90,7 +89,7 @@ def render(app):
         if ctx.get('embed') is True:
             # Parse & dump the spec to have it as properly formatted json
             specfile = os.path.join(app.confdir, ctx['spec'])
-            with io.open(specfile, encoding='utf-8') as specfp:
+            with open(specfile, encoding='utf-8') as specfp:
                 try:
                     spec_contents = yaml.safe_load(specfp)
                 except ValueError as ver:
diff --git a/tox.ini b/tox.ini
index d7ab500..35c76c8 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = py2, py3, docs
+envlist = py37, py38, py39, py310, py311, py312, docs
 
 [testenv]
 deps =