diff --git a/3rdparty/Sabre/VObject/Element/DateTime.php b/3rdparty/Sabre/VObject/Element/DateTime.php
index 63af858dd6..30e5c6ca86 100644
--- a/3rdparty/Sabre/VObject/Element/DateTime.php
+++ b/3rdparty/Sabre/VObject/Element/DateTime.php
@@ -70,20 +70,20 @@ class Sabre_VObject_Element_DateTime extends Sabre_VObject_Property {
                 $this->setValue($dt->format('Ymd\\THis'));
                 $this->offsetUnset('VALUE');
                 $this->offsetUnset('TZID');
-                $this->offsetSet('VALUE','DATETIME'); 
+                $this->offsetSet('VALUE','DATE-TIME');
                 break;
             case self::UTC :
                 $dt->setTimeZone(new DateTimeZone('UTC'));
                 $this->setValue($dt->format('Ymd\\THis\\Z'));
                 $this->offsetUnset('VALUE');
                 $this->offsetUnset('TZID');
-                $this->offsetSet('VALUE','DATETIME');
+                $this->offsetSet('VALUE','DATE-TIME');
                 break;
             case self::LOCALTZ :
                 $this->setValue($dt->format('Ymd\\THis'));
                 $this->offsetUnset('VALUE');
                 $this->offsetUnset('TZID');
-                $this->offsetSet('VALUE','DATETIME');
+                $this->offsetSet('VALUE','DATE-TIME');
                 $this->offsetSet('TZID', $dt->getTimeZone()->getName());
                 break; 
             case self::DATE :
diff --git a/3rdparty/Sabre/VObject/Element/MultiDateTime.php b/3rdparty/Sabre/VObject/Element/MultiDateTime.php
index 07f7e82c34..5e677f5e5b 100644
--- a/3rdparty/Sabre/VObject/Element/MultiDateTime.php
+++ b/3rdparty/Sabre/VObject/Element/MultiDateTime.php
@@ -60,7 +60,7 @@ class Sabre_VObject_Element_MultiDateTime extends Sabre_VObject_Property {
                     $val[] = $i->format('Ymd\\THis');
                 }
                 $this->setValue(implode(',',$val));
-                $this->offsetSet('VALUE','DATETIME'); 
+                $this->offsetSet('VALUE','DATE-TIME');
                 break;
             case Sabre_VObject_Element_DateTime::UTC :
                 $val = array();
@@ -69,7 +69,7 @@ class Sabre_VObject_Element_MultiDateTime extends Sabre_VObject_Property {
                     $val[] = $i->format('Ymd\\THis\\Z');
                 }
                 $this->setValue(implode(',',$val));
-                $this->offsetSet('VALUE','DATETIME');
+                $this->offsetSet('VALUE','DATE-TIME');
                 break;
             case Sabre_VObject_Element_DateTime::LOCALTZ :
                 $val = array();
@@ -77,7 +77,7 @@ class Sabre_VObject_Element_MultiDateTime extends Sabre_VObject_Property {
                     $val[] = $i->format('Ymd\\THis');
                 }
                 $this->setValue(implode(',',$val));
-                $this->offsetSet('VALUE','DATETIME');
+                $this->offsetSet('VALUE','DATE-TIME');
                 $this->offsetSet('TZID', $dt[0]->getTimeZone()->getName());
                 break; 
             case Sabre_VObject_Element_DateTime::DATE :