You have a JACE that has been running since AX-3.0, installed in a U.S. time zone that observes DST. Included in the AX-3.0 builds was a timezones.xml with “old” DST rules. See the DST section for related details. On it you have a station running, that includes an original history for a boolean point with two records like this:

01-Nov-06 8:00 AM EST {} {ok} On01-Nov-06
5:00 PM EST {} {ok} Off

The timestamp values shown are correct, this was a piece of equipment that came ON at 8:00am and OFF at 5:00pm, and on November 1st of 2006 it was indeed “Eastern Standard Time” (EST), as Daylight Savings Time had already ended on the last Sunday in October.

Since, you upgraded the JACE to AX-3.2, which uses updated 2007 rules in its timezones.xml file. Afterwards, when looking at the same two records for the example history, you see:

01-Nov-06 9:00:11 AM EDT {} {ok} On01-Nov-06
6:00:13 PM EDT {} {ok} Off

These timestamp values are incorrect, as the DST offset of 1 hour was “retroactively” applied using the new DST rules (even though these rules were not actually in effect at this time). However, those same new rules are required during this period in 2007 to correctly change the system clock and maintain accurate 2007 timestamps.

After upgrading the JACE to a more current NiagaraAX release, which uses the timezones.jar (historical time zone database) instead of timezones.xml, when you look again at the same two records for the example history, you see:

01-Nov-06 8:00:11 AM EST {} {ok} On01-Nov-06
5:00:13 PM EST {} {ok} Off

The timestamp values are correct, as the historical rules were used instead of the current (new) rules.