diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index fac1329a..a45d2a61 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -3,12 +3,12 @@ default_language_version:
 
 repos:
   - repo: https://github.com/asottile/pyupgrade
-    rev: v3.14.0
+    rev: v3.15.0
     hooks:
       - id: pyupgrade
         args: [ '--py38-plus' ]
   - repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: v4.4.0
+    rev: v4.5.0
     hooks:
       - id: trailing-whitespace
         exclude: setup.cfg
@@ -27,7 +27,7 @@ repos:
       - id: yamllint
         args: [ '--config-file=.yamllint.yaml' ]
   - repo: https://github.com/psf/black
-    rev: 23.9.1
+    rev: 23.10.1
     hooks:
       - id: black
         args: [ '--target-version=py38' ]
@@ -47,10 +47,10 @@ repos:
     hooks:
       - id: nbqa-black
         args: [ '--target-version=py38' ]
-        additional_dependencies: [ 'black==23.9.1' ]
+        additional_dependencies: [ 'black==23.10.1' ]
       - id: nbqa-pyupgrade
         args: [ '--py38-plus' ]
-        additional_dependencies: [ 'pyupgrade==3.14.0' ]
+        additional_dependencies: [ 'pyupgrade==3.15.0' ]
       - id: nbqa-isort
         args: [ '--settings-file=setup.cfg' ]
         additional_dependencies: [ 'isort==5.12.0' ]
@@ -66,12 +66,12 @@ repos:
       - id: pydocstyle
         args: [ '--config=setup.cfg' ]
   - repo: https://github.com/keewis/blackdoc
-    rev: v0.3.8
+    rev: v0.3.9
     hooks:
       - id: blackdoc
-        additional_dependencies: [ 'black==23.9.1' ]
+        additional_dependencies: [ 'black==23.10.1' ]
   - repo: https://github.com/python-jsonschema/check-jsonschema
-    rev: 0.27.0
+    rev: 0.27.1
     hooks:
       - id: check-github-workflows
       - id: check-readthedocs
diff --git a/requirements_docs.txt b/requirements_docs.txt
index 000a68b3..e6f53344 100644
--- a/requirements_docs.txt
+++ b/requirements_docs.txt
@@ -10,3 +10,4 @@ xclim==0.43
 pillow>=10.0.1 # not directly required, pinned by Snyk to avoid a vulnerability
 setuptools>=65.5.1 # not directly required, pinned by Snyk to avoid a vulnerability
 werkzeug>=3.0.1 # not directly required, pinned by Snyk to avoid a vulnerability
+tornado>=6.3.3 # not directly required, pinned by Snyk to avoid a vulnerability