On Feb 18, 2019, at 6:41 AM, Tim Parenti <tim@timtimeonline.com> wrote:
This, however, is where the need for a second zone for Vietnam arises. And indeed there are already two listed in zone1970.tab (Asia/Ho_Chi_Minh and Asia/Bangkok);
So Hanoi time has always had the same offset same as Bangkok time from 1970-01-01 00:00:00 UTC to the present, and, like Bangkok, has never had summer time/DST? If so, then is the reason that we have Link Asia/Bangkok Asia/Phnom_Penh # Cambodia Link Asia/Bangkok Asia/Vientiane # Laos but don't have, for example, Link Asia/Bangkok Asia/Hanoi # (North) Vietnam that Asia/Phnom_Penh and Asia/Vientiane existed as separate entries before being combined with Asia/Bangkok, so that we need to keep their entire around for backwards compatibility, but there had never been an Asia/Hanoi?