You can use the following Variables :
$scriptname : Script Name
$url : URL
$oldversion : Current Version
$version : Latest Version
$user : Username
$error : List of Errors
$sn : Site Name (Can be changed from Webuzo Admin panel -> Settings)

Note : You can use an IF for an Optional Variable in the following manner :
<if $VARIABLE_NAME>$VARIABLE_NAME</if>