diff --git a/lib/passport-cas.js b/lib/passport-cas.js
index 4951b15..52f1c33 100644
--- a/lib/passport-cas.js
+++ b/lib/passport-cas.js
@@ -95,7 +95,7 @@ function CasStrategy(options, verify) {
 
   this.cas = new CAS({
     base_url: this.casBaseUrl,
-    version: 2,
+    version: 3,
     external_pgt_url: this.casPgtUrl,
     ssl_cert: options.sslCert,
     ssl_key: options.sslKey,