diff --git a/doc/requirements.txt b/doc/requirements.txt
index db6a9394..6217bfed 100644
--- a/doc/requirements.txt
+++ b/doc/requirements.txt
@@ -4,5 +4,5 @@ sphinxcontrib-devhelp==1.0.2; python_version >= "3.5"
 sphinxcontrib-htmlhelp==2.0.1; python_version >= "3.5"
 sphinxcontrib-jsmath==1.0.1; python_version >= "3.5"
 sphinxcontrib-qthelp==1.0.3; python_version >= "3.5"
-sphinxcontrib-serializinghtml==1.1.5; python_version >= "3.5"
+sphinxcontrib-serializinghtml==1.1.9; python_version >= "3.5"
 django-typer==0.1.0