diff --git a/setup.py b/setup.py
index 6ae3eb7db..66e543794 100644
--- a/setup.py
+++ b/setup.py
@@ -72,7 +72,7 @@ base = [
     "ToJyutping==0.2.1",
     "typeguard==2.13.3",
     "webrtcvad",
-    "yacs",
+    "yacs~=0.1.8",
     "zhon",
 ]