From the Avaya PARTNER ACS / SMB Product News of March, 2007:
What software releases of PARTNER have the new Daylight Savings enhancement?
PARTNER ACS R7.0.91K
PARTNER ACS R6.85T
These versions create a new ADST calendar table that can be adjusted for new DST dates on that calendar.
What if I have a PARTNER ACS R7.0.91J or
PARTNER ACS 6.85S?
Built in to these releases is an enhancement called “Network Time Synchronization”. If you subscribe to
Incoming Caller ID; the time is sent along with the Caller ID information. PARTNER ACS (with the above releases) reads this information and automatically adjusts the system clock accordingly. Although this does not deactivate the Automatic Daylight Savings Time feature, it will automatically correct the clock.
These versions keep the "old" DST calendar, but automatically updates the system time on every Caller-ID call received on the switch.