diff --git a/signer/signer.go b/signer/signer.go
index 4f79bef2..40d23ec3 100644
--- a/signer/signer.go
+++ b/signer/signer.go
@@ -34,7 +34,7 @@ import (
 )
 
 // signingAgent is the unprotected header field used by signature.
-const signingAgent = "notation-go/1.2.0"
+const signingAgent = "notation-go/1.2.1"
 
 // GenericSigner implements notation.Signer and embeds signature.Signer
 type GenericSigner struct {