diff --git a/docs/prepare_env/requirements.txt b/docs/prepare_env/requirements.txt
index 65f5ec5..ca26c57 100644
--- a/docs/prepare_env/requirements.txt
+++ b/docs/prepare_env/requirements.txt
@@ -60,7 +60,7 @@ s3prl
 fire
 
 # cal LMD
-dlib
+dlib==19.24.2
 
 # debug
 ipykernel
@@ -72,4 +72,4 @@ setproctitle
 
 # Gradio GUI
 httpx==0.23.3
-gradio==4.16.0
\ No newline at end of file
+gradio==4.16.0