--- loncom/lti/ltiauth.pm	2018/05/14 19:56:05	1.11
+++ loncom/lti/ltiauth.pm	2018/05/14 20:10:15	1.12
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # Basic LTI Authentication Module
 #
-# $Id: ltiauth.pm,v 1.11 2018/05/14 19:56:05 raeburn Exp $
+# $Id: ltiauth.pm,v 1.12 2018/05/14 20:10:15 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -294,6 +294,12 @@ sub handler {
         $protocol = 'https';
     }
 
+    if (exists($params->{'oauth_callback'})) {
+        $Net::OAuth::PROTOCOL_VERSION = Net::OAuth::PROTOCOL_VERSION_1_0A;
+    } else {
+        $Net::OAuth::PROTOCOL_VERSION = Net::OAuth::PROTOCOL_VERSION_1_0;
+    }
+
     my ($itemid,$consumer_key,$secret);
     $consumer_key = $params->{'oauth_consumer_key'};
     if (ref($lti_by_key{$consumer_key}) eq 'ARRAY') {