diff --git a/Preferred-Chain.md b/Preferred-Chain.md
index 77c7c7d..353ed22 100644
--- a/Preferred-Chain.md
+++ b/Preferred-Chain.md
@@ -57,3 +57,16 @@ acme.sh  --issue -d example.com .....  --server letsencrypt    --preferred-chain
 ```
 
 
+3.  You can also set the default preferred chain for a specified CA(from v3.0.1).
+
+```
+acme.sh --set-default-chain  --preferred-chain "ISRG"   --server  letsencrypt
+```
+
+When you request a cert from letsencrypt in future, it will use the default preferred chain.
+
+
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