diff --git a/pyproject.toml b/pyproject.toml
index 103543a..0ef29bf 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -18,10 +18,10 @@ dependencies = [
 ]
 
 [project.optional-dependencies]
-dev = ["pytest>=8", "pypdf>=4"]
+dev = ["pytest>=8", "pypdf>=6.13.3"]
 
 [dependency-groups]
-dev = ["pytest>=8", "pypdf>=4"]
+dev = ["pytest>=8", "pypdf>=6.13.3"]
 
 [project.scripts]
 bookstack-to-pdf = "bookstack_to_pdf.__main__:main"
diff --git a/uv.lock b/uv.lock
index 54cca5c..2314c03 100644
--- a/uv.lock
+++ b/uv.lock
@@ -57,7 +57,7 @@ requires-dist = [
     { name = "beautifulsoup4", specifier = ">=4.12" },
     { name = "jinja2", specifier = ">=3" },
     { name = "pydantic", specifier = ">=2" },
-    { name = "pypdf", marker = "extra == 'dev'", specifier = ">=4" },
+    { name = "pypdf", marker = "extra == 'dev'", specifier = ">=6.13.3" },
     { name = "pytest", marker = "extra == 'dev'", specifier = ">=8" },
     { name = "pyyaml", specifier = ">=6" },
     { name = "weasyprint", specifier = ">=68.1" },
@@ -66,7 +66,7 @@ provides-extras = ["dev"]
 
 [package.metadata.requires-dev]
 dev = [
-    { name = "pypdf", specifier = ">=4" },
+    { name = "pypdf", specifier = ">=6.13.3" },
     { name = "pytest", specifier = ">=8" },
 ]
 
@@ -715,14 +715,14 @@ wheels = [
 
 [[package]]
 name = "pypdf"
-version = "6.10.2"
+version = "6.13.3"
 source = { registry = "https://pypi.org/simple" }
 dependencies = [
     { name = "typing-extensions", marker = "python_full_version < '3.11'" },
 ]
-sdist = { url = "https://files.pythonhosted.org/packages/7b/3f/9f2167401c2e94833ca3b69535bad89e533b5de75fefe4197a2c224baec2/pypdf-6.10.2.tar.gz", hash = "sha256:7d09ce108eff6bf67465d461b6ef352dcb8d84f7a91befc02f904455c6eea11d", size = 5315679, upload-time = "2026-04-15T16:37:36.978Z" }
+sdist = { url = "https://files.pythonhosted.org/packages/17/18/9947cc201af9ccf76720fd3347bf4f70eb882ce3fcf4cb05f7443e4cf871/pypdf-6.13.3.tar.gz", hash = "sha256:f3cb822769725f1bac658c406cfc9460399043f3750c2d3e4650e0a85eacabd7", size = 6484063, upload-time = "2026-06-17T15:22:00.898Z" }
 wheels = [
-    { url = "https://files.pythonhosted.org/packages/0c/d6/1d5c60cc17bbdf37c1552d9c03862fc6d32c5836732a0415b2d637edc2d0/pypdf-6.10.2-py3-none-any.whl", hash = "sha256:aa53be9826655b51c96741e5d7983ca224d898ac0a77896e64636810517624aa", size = 336308, upload-time = "2026-04-15T16:37:34.851Z" },
+    { url = "https://files.pythonhosted.org/packages/94/56/2967e621598987905fb8cdfadd8f8de6b5c68c9351f0523c4df8409f28f1/pypdf-6.13.3-py3-none-any.whl", hash = "sha256:c6e3f86afb625791510b02ad5480e94b63970bb957df75d44657c282ecc52224", size = 347288, upload-time = "2026-06-17T15:21:59.512Z" },
 ]
 
 [[package]]