diff --git a/docs/requirements.txt b/docs/requirements.txt
index c2d56bf91..db6c80998 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -39,7 +39,7 @@ sphinx_rtd_theme
 textgrid
 timer
 ToJyutping
-typeguard
+typeguard==2.13.3
 webrtcvad
 websockets
 yacs~=0.1.8