Hello: We are trying to simulate the DST in our test environment. As part of this process, we want to modify the rules so that the short day and long day can be any day we choose. Currently, we chose lastSun of Feb as short day and lastSun of March as long day. Can you please provide us an example as to what needs to be changed in the "northamerica" file? We have changed the following in "northamerica" file: ---------------------------- # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S Rule US 2007 max - Feb lastSun 2:00 0:00 D Rule US 2007 max - Mar lastSun 2:00 0 S --------------------------------------- Is there any other place we need to change in "northamerica" file? This northamerica file is from the tzdata version "tzdata2007k" The problem with this change is that one hour is being added to every hour subsequent to last Sunday in Feb until the actual Short day (March 9). After March 9, one hour is substracted from wall time from every hour until the actual Long Day (Nov 2). Are there any known bugs/fixes to "javazic" code? Your help will be very much appreciated. Best Regards, Praveen