diff --git a/requirements.txt b/requirements.txt
index 382b939b..e01f6582 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,3 +2,8 @@ Sphinx>=4.1
 sphinx-rtd-theme>=0.5
 sphinx-tabs>=1.3,<=3.2
 sphinx-version-warning>=1.1
+sphinxcontrib-applehelp<1.0.8
+sphinxcontrib-devhelp<1.0.6
+sphinxcontrib-htmlhelp<2.0.5
+sphinxcontrib-serializinghtml<1.1.10
+sphinxcontrib-qthelp<1.0.7