diff --git a/lib/classes/Swift/Transport/StreamBuffer.php b/lib/classes/Swift/Transport/StreamBuffer.php
index a2e08b8c4..6cd4a8ca6 100644
--- a/lib/classes/Swift/Transport/StreamBuffer.php
+++ b/lib/classes/Swift/Transport/StreamBuffer.php
@@ -113,7 +113,11 @@ public function setParam($param, $value)
      */
     public function startTLS()
     {
-        return stream_socket_enable_crypto($this->_stream, true, STREAM_CRYPTO_METHOD_TLS_CLIENT);
+        // STREAM_CRYPTO_METHOD_TLS_CLIENT only allow tls1.0 connections (some php versions)
+        // To support modern tls we allow explicit tls1.0, tls1.1, tls1.2
+        // Ssl3 and older are not allowed because they are vulnerable
+        // @TODO make tls arguments configurable
+        return stream_socket_enable_crypto($this->_stream, true, STREAM_CRYPTO_METHOD_TLSv1_0_CLIENT | STREAM_CRYPTO_METHOD_TLSv1_1_CLIENT | STREAM_CRYPTO_METHOD_TLSv1_2_CLIENT);
     }
 
     /**