diff --git a/phpgwapi/inc/horde/Horde/SyncML/Command/Put.php b/phpgwapi/inc/horde/Horde/SyncML/Command/Put.php
index c99a7b0c16..a1bcc14251 100644
--- a/phpgwapi/inc/horde/Horde/SyncML/Command/Put.php
+++ b/phpgwapi/inc/horde/Horde/SyncML/Command/Put.php
@@ -133,7 +133,7 @@ class Horde_SyncML_Command_Put extends Horde_SyncML_Command {
 						break;
 
 					case 'SourceRef':
-						$this->_sourceReference = trim($this->_chars);
+						$this->_sourceReference = strtolower(trim($this->_chars));
 						break;
 
 					case 'Tx-Pref':
diff --git a/phpgwapi/inc/horde/Horde/SyncML/State.php b/phpgwapi/inc/horde/Horde/SyncML/State.php
index 3635cab7cb..eca8b74a78 100644
--- a/phpgwapi/inc/horde/Horde/SyncML/State.php
+++ b/phpgwapi/inc/horde/Horde/SyncML/State.php
@@ -985,6 +985,7 @@ class Horde_SyncML_State {
 
 	function getPreferedContentTypeClient($_sourceLocURI, $_targetLocURI = null) {
 		$deviceInfo = $this->getClientDeviceInfo();
+		$_sourceLocURI = strtolower($_sourceLocURI);
 
 		if(isset($deviceInfo['dataStore'][$_sourceLocURI]['maxGUIDSize']['contentType'])) {
 			$this->_maxGUIDSize = $deviceInfo['dataStore'][$this->_sourceURI]['maxGUIDSize']['contentType'];