diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 9cb029a..58ca9e2 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -1,12 +1,12 @@
 repos:
   - repo: https://github.com/pre-commit/mirrors-mypy
-    rev: v0.991
+    rev: v1.10.1
     hooks:
       - id: mypy
         args: [--ignore-missing-imports]
 
   - repo: https://github.com/charliermarsh/ruff-pre-commit
-    rev: v0.2.1
+    rev: v0.5.2
     hooks:
       # Run the linter.
       - id: ruff
diff --git a/README.md b/README.md
index 6deb543..0fc961c 100644
--- a/README.md
+++ b/README.md
@@ -95,3 +95,22 @@ To enable sorting of imports using ruff's isort functionality, add `"I"` to the
 `python-lsp-ruff` supports code actions as given by possible fixes by `ruff`. `python-lsp-ruff` also supports [unsafe fixes](https://docs.astral.sh/ruff/linter/#fix-safety).
 Fixes considered unsafe by `ruff` are marked `(unsafe)` in the code action.
 The `Fix all` code action *only* consideres safe fixes.
+
+## Debugging
+
+The log level can be set via the `cmd` option of `pylsp`:
+
+```lua
+lspconfig.pylsp.setup {
+  cmd = {"pylsp", "-vvv", "--log-file", "/tmp/lsp.log"},
+  settings = {
+    pylsp = {
+      plugins = {
+        ruff = {
+          enabled = true,
+        },
+      }
+    }
+  }
+}
+```
diff --git a/pylsp_ruff/plugin.py b/pylsp_ruff/plugin.py
index ed6156f..833f16b 100644
--- a/pylsp_ruff/plugin.py
+++ b/pylsp_ruff/plugin.py
@@ -210,7 +210,7 @@ def create_diagnostic(check: RuffCheck, settings: PluginSettings) -> Diagnostic:
     # Ruff intends to implement severity codes in the future,
     # see https://github.com/charliermarsh/ruff/issues/645.
     severity = DiagnosticSeverity.Warning
-    if check.code == "E999" or check.code[0] == "F":
+    if check.code == "None" or check.code == "E999" or check.code[0] == "F":
         severity = DiagnosticSeverity.Error
 
     # Check if check.code starts contained in given severities
diff --git a/pyproject.toml b/pyproject.toml
index 8787263..88730ca 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -7,7 +7,7 @@ name = "python-lsp-ruff"
 authors = [
   {name = "Julian Hossbach", email = "julian.hossbach@gmx.de"}
 ]
-version = "2.2.1"
+version = "2.2.2"
 description = "Ruff linting plugin for pylsp"
 readme = "README.md"
 requires-python = ">=3.8"