diff --git a/src/PaypalIPN.php b/src/PaypalIPN.php
index 9d4d2af..b82e752 100644
--- a/src/PaypalIPN.php
+++ b/src/PaypalIPN.php
@@ -103,7 +103,7 @@ function verifyIPN()
         curl_setopt($ch, CURLOPT_POST, 1);
         curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
         curl_setopt($ch, CURLOPT_POSTFIELDS, $req);
-        curl_setopt($ch, CURLOPT_SSLVERSION, 4);
+        curl_setopt($ch, CURLOPT_SSLVERSION, 6);
         curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 1);
         curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2);
         if ($this->use_local_certs)