 1991
and switched back in 2006.
To use the database on a <a
href="https://en.wikipedia.org/wiki/POSIX"><abbr
title="Portable Operating System Interface">POSIX</abbr>.1-2024</a>
implementation set the <code><abbr>TZ</abbr></code>
environment variable to the location’s full name,
e.g., <code><abbr>TZ</abbr>="America/New_York"</code>.</p>
<p>
Associated with each timezone is a history of offsets from
<a href="https://en.wikipedia.org/wiki/Universal_Time">Universal
Time</a> (<abbr>UT</abbr>), which is <a
hre