diff --git a/docs/requirements.txt b/docs/requirements.txt
index 434d868..343d2cb 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -8,3 +8,4 @@ nbsphinx
 
 # Required to build sphinx (2021-10-28)
 docutils<0.18
+recommonmark