diff --git a/manifest.php b/manifest.php
index 50686aaa..6f4d1b49 100755
--- a/manifest.php
+++ b/manifest.php
@@ -35,7 +35,7 @@
 	'label' => 'LTI library',
     'description' => 'TAO LTI library and helpers',
     'license' => 'GPL-2.0',
-    'version' => '3.0.0',
+    'version' => '3.1.0',
 	'author' => 'Open Assessment Technologies SA',
 	'requires' => array(
 	   'tao' => '>=9.0.0'
diff --git a/models/classes/LtiVariableMissingException.php b/models/classes/LtiVariableMissingException.php
new file mode 100644
index 00000000..9fe64263
--- /dev/null
+++ b/models/classes/LtiVariableMissingException.php
@@ -0,0 +1,35 @@
+<?php
+/**
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; under version 2
+ * of the License (non-upgradable).
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ *
+ * Copyright (c) 2017 (original work) Open Assessment Technologies SA
+ *
+ */
+namespace oat\taoLti\models\classes;
+
+use oat\taoLti\models\classes\LtiMessages\LtiErrorMessage;
+
+class LtiVariableMissingException extends \taoLti_models_classes_LtiException
+    implements \common_log_SeverityLevel
+{
+    public function __construct($variableName)
+    {
+        parent::__construct('Undefined LTI variable '.$variableName, LtiErrorMessage::ERROR_MISSING_PARAMETER);
+    }
+
+    public function getSeverity() {
+        return \common_Logger::DEBUG_LEVEL;
+    }
+}
\ No newline at end of file
diff --git a/models/classes/class.LtiLaunchData.php b/models/classes/class.LtiLaunchData.php
index add572ba..f8b5424c 100755
--- a/models/classes/class.LtiLaunchData.php
+++ b/models/classes/class.LtiLaunchData.php
@@ -19,7 +19,7 @@
  * 
  */
 
-use oat\taoLti\models\classes\LtiMessages\LtiErrorMessage;
+use oat\taoLti\models\classes\LtiVariableMissingException;
 
 class taoLti_models_classes_LtiLaunchData
 {
@@ -114,7 +114,7 @@ public function getVariable($key) {
         if (isset($this->variables[$key])) {
             return $this->variables[$key];
         } else {
-            throw new taoLti_models_classes_LtiException('Undefined LTI variable '.$key, LtiErrorMessage::ERROR_MISSING_PARAMETER);
+            throw new LtiVariableMissingException($key);
         }
     }
     
diff --git a/models/classes/class.LtiUser.php b/models/classes/class.LtiUser.php
index 56449025..c559bdcb 100755
--- a/models/classes/class.LtiUser.php
+++ b/models/classes/class.LtiUser.php
@@ -1,4 +1,5 @@
 <?php
+use oat\taoLti\models\classes\LtiVariableMissingException;
 /**  
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -81,10 +82,18 @@ public function getPropertyValues($property) {
 	    	    $returnValue = $this->roles;
 	    	    break;
             case PROPERTY_USER_FIRSTNAME :
-                $returnValue = [$this->getLaunchData()->getUserGivenName()];
+                try {
+                    $returnValue = [$this->getLaunchData()->getUserGivenName()];
+                } catch (LtiVariableMissingException $e) {
+                    $returnValue = '';
+                }
                 break;
             case PROPERTY_USER_LASTNAME :
-                $returnValue = [$this->getLaunchData()->getUserFamilyName()];
+                try {
+                    $returnValue = [$this->getLaunchData()->getUserFamilyName()];
+                } catch (LtiVariableMissingException $e) {
+                    $returnValue = '';
+                }
                 break;
 	    	default:
 	    	    common_Logger::d('Unkown property '.$property.' requested from '.__CLASS__);
diff --git a/scripts/update/class.Updater.php b/scripts/update/class.Updater.php
index c776d48c..0d1b1e29 100644
--- a/scripts/update/class.Updater.php
+++ b/scripts/update/class.Updater.php
@@ -73,6 +73,6 @@ public function update($initialVersion)
 
             $this->setVersion('2.1.0');
         }
-        $this->skip('2.1.0', '3.0.0');
+        $this->skip('2.1.0', '3.1.0');
     }
 }