diff --git a/CHANGELOG.md b/CHANGELOG.md
index 58ed508..7e73cbe 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 All notable changes to this project will be documented in this file.
 
+## [0.4.5] 2026-01-09
+### Fixed
+- Documentation build with constraint `sphinx<9.0.0`.
+
 ## [0.4.4] 2026-01-09
 ### Added
 - `SizedGenerator` class wrapper.
diff --git a/CITATION.cff b/CITATION.cff
index 52054c3..d7c23e7 100644
--- a/CITATION.cff
+++ b/CITATION.cff
@@ -17,5 +17,5 @@ keywords:
   - tools
   - utilities
 license: MIT
-version: 0.4.4
+version: 0.4.5
 date-released: '2026-01-09'
diff --git a/docs/requirements.txt b/docs/requirements.txt
index e90e849..84084bb 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -1,3 +1,4 @@
 # -*- coding: utf-8 -*-
 
 sphinx-immaterial>=0.11.14
+sphinx<9.0.0
diff --git a/pyproject.toml b/pyproject.toml
index 32979df..1eb7b12 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -93,7 +93,7 @@ dev = [
     "pythonwrench",
     "ruff>=0.12.0",
     "setuptools",
-    "sphinx",
+    "sphinx<9.0.0",
     "sphinx-immaterial>=0.11.14",
     "twine",
 ]
diff --git a/src/pythonwrench/__init__.py b/src/pythonwrench/__init__.py
index 8a6420e..034c4ad 100644
--- a/src/pythonwrench/__init__.py
+++ b/src/pythonwrench/__init__.py
@@ -9,7 +9,7 @@
 __license__ = "MIT"
 __maintainer__ = "Étienne Labbé (Labbeti)"
 __status__ = "Development"
-__version__ = "0.4.4"
+__version__ = "0.4.5"
 
 
 # Re-import for language servers