diff --git a/acme/api/internal/sender/useragent.go b/acme/api/internal/sender/useragent.go
index 935bc66c..268756d7 100644
--- a/acme/api/internal/sender/useragent.go
+++ b/acme/api/internal/sender/useragent.go
@@ -5,10 +5,10 @@ package sender
 
 const (
 	// ourUserAgent is the User-Agent of this underlying library package.
-	ourUserAgent = "xenolf-acme/4.1.3"
+	ourUserAgent = "xenolf-acme/4.2.0"
 
 	// ourUserAgentComment is part of the UA comment linked to the version status of this underlying library package.
 	// values: detach|release
 	// NOTE: Update this with each tagged release.
-	ourUserAgentComment = "detach"
+	ourUserAgentComment = "release"
 )