diff --git a/proxyserver/main.go b/proxyserver/main.go
index 01264642..f1fcec72 100644
--- a/proxyserver/main.go
+++ b/proxyserver/main.go
@@ -133,7 +133,11 @@ func main() {
 		panic(err)
 	}
 
-	tlscfg := &tls.Config{Certificates: []tls.Certificate{cert}}
+	tlscfg := &tls.Config{
+		Certificates: []tls.Certificate{cert},
+		MinVersion:   tls.VersionTLS12,
+		MaxVersion:   tls.VersionTLS13,
+	}
 	serv := http.Server{
 		Addr:      ServerAddress,
 		Handler:   mux,