IANA time zone database - cutoff date
Alan Barret 2013-09-19 09:05:08 http://mm.icann.org/pipermail/tz/2013-September/020290.html
In the short term, I think that the tz project should stick to the existing practice of using 1970 as a cutoff date.
In the long term, think that the tz project should attempt to provide as much high-quality data as is reasonably feasible
Stephen Colebourne 2013-09-18 12:22:11 http://mm.icann.org/pipermail/tz/2013-September/020259.html
Pre-1970 data matters to some more than others. I can see a range of positions:
a) delete all pre-1970 data
b) only have Zones for areas distinct after 1970, other IDs are Links, full data where available for each Zone
c) only have IDs for areas distinct after 1970, full data where available for each ID
d) create new IDs where data only differs before 1970
I'm arguing for (c), which I previously believed was the tzdb's goal. The data deletion is based on (b).