These attributes are currently in use:
aclGroupAddr, cn, givenName, icsAllowedServiceAccess, icsCalendar, icsCalendarOwned, icsDWPHost, icsExtendedUserPrefs,icsFirstDay, icsPartition, icsSet, icsStatus, icsSubscribed, icsTimezone, mail, mailAlternateAddress, preferredLanguage, sn, uid, userPassword
These attributes are reserved but not currently used:
icsDefaultSet, icsExtended, icsFreeBusy, icsGeo, icsPreferredHost, icsQuota, nswcalDisallowAccess