diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index f06c477..20dc0f3 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -7,7 +7,25 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python: [3.5, 3.6, 3.7, 3.8, 3.9]
+        python: [3.8, 3.9, "3.10"]
+    steps:
+    - name: Check out code
+      uses: actions/checkout@v2
+    - name: Setup Python
+      uses: actions/setup-python@v2
+      with:
+        python-version: ${{ matrix.python }}
+    - name: Install Dependencies
+      run: |
+        pip install tox
+    - name: Run lint
+      run: tox -e flake8
+  lint-old-python:
+    name: Lint on older Python versions
+    runs-on: ubuntu-20.04
+    strategy:
+      matrix:
+        python: [3.5, 3.6, 3.7]
     steps:
     - name: Check out code
       uses: actions/checkout@v2
diff --git a/tox.ini b/tox.ini
index b6c5b72..b4057ae 100644
--- a/tox.ini
+++ b/tox.ini
@@ -4,10 +4,11 @@ envlist = flake8, py3
 skip_missing_interpreters = True
 
 [testenv]
-commands = /bin/bash -c 'py.test -v'
-
+allowlist_externals =
+  /bin/bash
 deps =
     -r{toxinidir}/requirements.txt
+commands = /bin/bash -c 'py.test -v'
 
 [testenv:flake8]
 commands = flake8 reactive lib tests unit_tests
@@ -15,9 +16,17 @@ commands = flake8 reactive lib tests unit_tests
 [testenv:func]
 basepython = python3
 deps = -r{toxinidir}/test-requirements.txt
-whitelist_externals = ln mkdir readlink rm juju
-setenv = CHARM_LAYERS_DIR=/tmp/charm-builds/_tmp/layers
-passenv = HOME
+allowlist_externals =
+  /bin/bash
+  /bin/ln
+  /bin/mkdir
+  /bin/readlink
+  /bin/rm
+  /snap/bin/juju
+setenv =
+  CHARM_LAYERS_DIR=/tmp/charm-builds/_tmp/layers
+passenv =
+  HOME
 commands =
     /bin/rm -rf /tmp/charm-builds/_tmp /tmp/charm-builds/minimal
     /bin/rm -rf /tmp/charm-builds/_tmp /tmp/charm-builds/minimal-binary-wheels
@@ -32,6 +41,8 @@ commands =
 
 
 [flake8]
+# E741: ambiguous variable name
+# W504: # line break after binary operator (have to ignore either this or W503)
 ignore =
-    E741,  # ambiguous variable name
-    W504   # line break after binary operator (have to ignore either this or W503)
+    E741,
+    W504
diff --git a/wheelhouse.txt b/wheelhouse.txt
index 2437af5..2a8335e 100644
--- a/wheelhouse.txt
+++ b/wheelhouse.txt
@@ -10,8 +10,13 @@ Jinja2==2.10;python_version >= '3.0' and python_version <= '3.4' # py3 trusty
 Jinja2==2.11;python_version == '2.7' or python_version == '3.5'  # py27, py35
 Jinja2;python_version >= '3.6' # py36 and on
 
+# Cython is required to build PyYAML. To find out the supported versions check
+# https://github.com/cython/cython/issues/2800
+Cython
+
 PyYAML==5.2;python_version >= '3.0' and python_version <= '3.4' # py3 trusty
-PyYAML<5.4;python_version == '2.7' or python_version >= '3.5'  # all else
+PyYAML<5.4;python_version == '2.7' or python_version <= '3.6'  # xenial and bionic
+PyYAML<7.0.0;python_version >= '3.7'  # >= focal
 
 MarkupSafe<2.0.0;python_version < '3.6'
 MarkupSafe<2.1.0;python_version == '3.6' # Just for python 3.6