diff --git a/src/go.mod b/src/go.mod
index b5045a6..ac2652f 100644
--- a/src/go.mod
+++ b/src/go.mod
@@ -1,6 +1,6 @@
 module github.com/sunbk201/ua3f
 
-go 1.21.3
+go 1.19
 
 require (
 	github.com/dlclark/regexp2 v1.11.4
diff --git a/src/main.go b/src/main.go
index 29a036e..9d6b715 100644
--- a/src/main.go
+++ b/src/main.go
@@ -388,6 +388,13 @@ func Socks5Forward(client, target net.Conn, destAddrPort string) {
 	}
 }
 
+func min(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}
+
 func CopyPileline(dst io.Writer, src io.Reader, destAddrPort string) {
 	buf := make([]byte, RDBUF)
 	nr, err := src.Read(buf)