diff --git a/src/pkg/crypto/tls/handshake_server.go b/src/pkg/crypto/tls/handshake_server.go
index 6c40489..0c96a2b 100644
--- a/src/pkg/crypto/tls/handshake_server.go
+++ b/src/pkg/crypto/tls/handshake_server.go
@@ -98,7 +98,7 @@
 	if !ok {
 		return false, c.sendAlert(alertUnexpectedMessage)
 	}
-	c.vers, ok = mutualVersion(hs.clientHello.vers)
+	c.vers, ok = config.mutualVersion(hs.clientHello.vers)
 	if !ok {
 		return false, c.sendAlert(alertProtocolVersion)
 	}
@@ -203,7 +203,7 @@
 	if hs.sessionState.vers > hs.clientHello.vers {
 		return false
 	}
-	if vers, ok := mutualVersion(hs.sessionState.vers); !ok || vers != hs.sessionState.vers {
+	if vers, ok := c.config.mutualVersion(hs.sessionState.vers); !ok || vers != hs.sessionState.vers {
 		return false
 	}