[tz] Version in zoneinfo files?

Guy Harris guy at alum.mit.edu
Thu Oct 29 00:29:23 UTC 2015

On Oct 28, 2015, at 5:23 PM, Lester Caine <lester at lsces.co.uk> wrote:

> On 29/10/15 00:12, Guy Harris wrote:
>>>> The major problem all the time is identifying just what rules were applied when processing historic data, which may actually only be a current meeting diary.
>> If by "historic data" you mean "pre-1970 data", I'm not sure why that would be needed for a current meeting diary, and it's not the major problem *all* the time, it's a problem for people using the tzdb to try to convert between UTC ("proleptic UTC"?) and local time for times prior to the Epoch, which might be a significant subset of the users of the tzdb, but it's still a (proper) subset of those users.
> See my other post ... If a user only has a post-1970 TZ set of data but
> then looks at some historic material they see the wrong times and
> possibly dates. Agreed it would not affect many people, but with the
> growing interest in family history it's a growing area of interest.

If a user has a *full* TZ set of data and then looks at some historic material they may see the wrong times and possibly dates, if the pre-1970 information is wrong. :-)

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