tzdb Release 2017b

Changelog (from NEWS)

Briefly: Haiti has resumed DST.

  Changes to past and future timestamps

    Haiti resumed observance of DST in 2017.  (Thanks to Steffen Thorsen.)

  Changes to past timestamps

    Liberia changed from -004430 to +00 on 1972-01-07, not 1972-05-01.

    Use "MMT" to abbreviate Liberia's time zone before 1972, as "-004430"
    is one byte over the POSIX limit.  (Problem reported by Derick Rethans.)

  Changes to code

    The reference localtime implementation now falls back on the
    current US daylight-saving transition rules rather than the
    1987-2006 rules.  This fallback occurs only when (1) the TZ
    environment variable has a value like "AST4ADT" that asks
    for daylight saving time but does not specify the rules, (2) there
    is no file by that name, and (3) the TZDEFRULES file cannot be
    loaded.  (Thanks to Tom Lane.)