diff --git a/docs/doc-requirements.txt b/docs/doc-requirements.txt
index 19f9313150..515433d366 100644
--- a/docs/doc-requirements.txt
+++ b/docs/doc-requirements.txt
@@ -1,3 +1,6 @@
+# needed because m2r uses deprecated APIs
+# m2r is depended on by sphinxcontrib-openapi
+docutils<0.19
 ipykernel
 jinja2
 jupyter_client