diff --git a/ReflexUtils.ftl b/ReflexUtils.ftl
index a73c1fa..574d0a2 100644
--- a/ReflexUtils.ftl
+++ b/ReflexUtils.ftl
@@ -2,8 +2,7 @@
 <#-- Concat reflex timestamp with reflex time zone and format this date in ISO UTC format -->
 <#-- --------------------------------------------------------------------------------------- -->
 <#function RfxDateTimetoUTC rfxdatetime offset >
-  <#assign datetimeUTC = JsonUtil.createUTCDateTime(rfxdatetime,time_zone_rfx , "yyyy-MM-dd'T'HH:mm:ss") />
-  <#return (datetimeUTC)>
+  <#return (rfxdatetime?datetime("yyyy-MM-dd'T'HH:mm:ss")?iso_utc)>
 </#function>
 
 <#-- --------------------------------------------------------------------------------------- -->