diff --git a/.devcontainer/devcontainer.json b/.devcontainer/devcontainer.json
index 72216aa15..b5629a19e 100644
--- a/.devcontainer/devcontainer.json
+++ b/.devcontainer/devcontainer.json
@@ -5,7 +5,7 @@
   "appPort": "9123:8123",
   "postCreateCommand": "pre-commit install",
   "runArgs": ["-e", "GIT_EDITOR=code --wait", "--privileged"],
-  "containerEnv": {"NVM_DIR":"/usr/local/share/nvm"},
+  "containerEnv": { "NVM_DIR": "/usr/local/share/nvm" },
   "extensions": [
     "ms-python.python",
     "ms-python.vscode-pylance",
@@ -22,7 +22,7 @@
     "python.linting.pylintEnabled": true,
     "python.linting.enabled": true,
     "python.formatting.provider": "black",
-    "python.formatting.blackArgs": ["--target-version", "py38"],
+    "python.formatting.blackArgs": ["--target-version", "py39"],
     "python.formatting.blackPath": "/usr/local/bin/black",
     "python.linting.banditPath": "/usr/local/bin/bandit",
     "python.linting.flake8Path": "/usr/local/bin/flake8",
diff --git a/pylintrc b/pylintrc
index 3c3e6b39d..c0cee4347 100644
--- a/pylintrc
+++ b/pylintrc
@@ -4,6 +4,9 @@ jobs=2
 
 good-names=id,i,j,k,ex,Run,_,fp,T
 
+extension-pkg-whitelist=
+  ciso8601
+
 # Reasons disabled:
 # format - handled by black
 # locally-disabled - it spams too much
diff --git a/requirements_tests.txt b/requirements_tests.txt
index 7604b9974..26ccf4ac1 100644
--- a/requirements_tests.txt
+++ b/requirements_tests.txt
@@ -5,7 +5,7 @@ flake8-docstrings==1.6.0
 flake8==3.9.2
 pre-commit==2.13.0
 pydocstyle==6.1.1
-pylint==2.8.3
+pylint==2.9.1
 pytest-aiohttp==0.3.0
 pytest-asyncio==0.12.0 # NB!: Versions over 0.12.0 breaks pytest-aiohttp (https://github.com/aio-libs/pytest-aiohttp/issues/16)
 pytest-cov==2.12.1
diff --git a/supervisor/resolution/checks/base.py b/supervisor/resolution/checks/base.py
index 30a6cf560..4e2a8c7ba 100644
--- a/supervisor/resolution/checks/base.py
+++ b/supervisor/resolution/checks/base.py
@@ -49,7 +49,7 @@ class CheckBase(ABC, CoreSysAttributes):
     @property
     def slug(self) -> str:
         """Return the check slug."""
-        return self.__class__.__module__.split(".")[-1]
+        return self.__class__.__module__.rsplit(".", maxsplit=1)[-1]
 
     @abstractmethod
     async def run_check(self) -> None:
diff --git a/supervisor/resolution/evaluations/base.py b/supervisor/resolution/evaluations/base.py
index eab5d3d6a..93f4bc268 100644
--- a/supervisor/resolution/evaluations/base.py
+++ b/supervisor/resolution/evaluations/base.py
@@ -46,7 +46,7 @@ class EvaluateBase(ABC, CoreSysAttributes):
     @property
     def slug(self) -> str:
         """Return the check slug."""
-        return self.__class__.__module__.split(".")[-1]
+        return self.__class__.__module__.rsplit(".", maxsplit=1)[-1]
 
     @property
     @abstractproperty
diff --git a/tox.ini b/tox.ini
index 3ff0c7fdb..f2ae14333 100644
--- a/tox.ini
+++ b/tox.ini
@@ -21,4 +21,4 @@ commands =
 [testenv:black]
 basepython = python3
 commands =
-    black --target-version py38 --check supervisor tests setup.py
+    black --target-version py39 --check supervisor tests setup.py