<P>USA saving time changes are included in PostgreSQL release 8.0.[4+],
    and all later major releases, e.g. 8.1.  Canada and Western Australia
    changes are included in 8.0.[10+], 8.1.[6+], and all later major
    releases.  PostgreSQL releases prior to 8.0 use the operating system's
    timezone database for daylight saving information.</P>