By default, time stamps on files referenced by [Files] section entries are saved and restored as local times. This means that if a particular file has a time stamp of 01:00 local time at compile time, Setup will extract the file with a time stamp of 01:00 local time, regardless of the user's time zone setting or whether DST is in effect.

If TimeStampsInUTC is set to yes, time stamps will be saved and restored in UTC -- the native time format of Win32 and NTFS. In this mode, a file with a time stamp of 01:00 local time in New York will have a time stamp of 06:00 local time when installed in London.