* tz-link.html: Update URLs.

tz-link.html

@@ -82,11 +82,12 @@ title="Berkeley Software Distribution">BSD</abbr></a>,
 <a href="https://www.openbsd.org">Open<abbr>BSD</abbr></a>,
 <a href="https://www.chromium.org/chromium-os">Chromium OS</a>,
 <a href="https://cygwin.com">Cygwin</a>,
+<a href="https://mariadb.org">MariaDB</a>,
 <a href="https://en.wikipedia.org/wiki/MINIX">MINIX</a>,
 <a href="https://www.mysql.com">MySQL</a>,
 <a href="https://en.wikipedia.org/wiki/WebOS"><abbr
 title="Web Operating System">webOS</abbr></a>,
-<a href="https://ibm.com/aix"><abbr
+<a href="https://en.wikipedia.org/wiki/IBM_AIX"><abbr
 title="Advanced Interactive eXecutive">AIX</abbr></a>,
 <a href="https://en.wikipedia.org/wiki/BlackBerry_10">BlackBerry 10</a>,
 <a href="https://www.apple.com/ios"><abbr
@@ -168,7 +169,8 @@ then <samp>za</samp> through <samp>zz</samp>, then <samp>zza</samp>
 through <samp>zzz</samp>, and so on).
 Since version 2016h, each release has contained a text file named
 "<samp>version</samp>" whose first (and currently only) line is the version.
-The releases are also available in an
+Older releases are <a href="https://ftp.iana.org/tz/releases/">archived</a>,
+and are also available in an
 <a href="ftp://ftp.iana.org/tz/releases/"><abbr
 title="File Transfer Protocol">FTP</abbr> directory</a> via a
 less-secure protocol.</p>
@@ -827,10 +829,10 @@ zones and daylight saving time</a>.</dd>
 Chile's official time (in Spanish)</a>.</dd>
 <dt>China</dt>
 <dd>The Hong Kong Observatory maintains a
-<a href="https://www.hko.gov.hk/gts/time/Summertime.htm">history of
+<a href="https://www.hko.gov.hk/en/gts/time/Summertime.htm">history of
  summer time in Hong Kong</a>,
 and Macau's Meteorological and Geophysical Bureau maintains a <a
-href="http://www.smg.gov.mo/smg/geophysics/e_t_Summer%20Time.htm">similar
+href="https://www.smg.gov.mo/en/subpage/224/page/174">similar
 history for Macau</a>.
 Unfortunately the latter is incomplete and has errors.</dd>
 <dt>Czech Republic</dt>
@@ -866,7 +868,7 @@ href="https://www.dia.govt.nz/Daylight-Saving-History">History of
 Daylight Saving</a>.</dd>
 <dt>Singapore</dt>
 <dd><a id="Singapore"
-href="http://www.math.nus.edu.sg/~mathelmr/teaching/timezone.html">Why
+href="https://web.archive.org/web/20190822231045/http://www.math.nus.edu.sg/~mathelmr/teaching/timezone.html">Why
 is Singapore in the "Wrong" Time Zone?</a> details the
 history of legal time in Singapore and Malaysia.</dd>
 <dt>United Kingdom</dt>
@@ -881,7 +883,7 @@ Time Zone Proceedings</a> lists changes to time zone boundaries.</dd>
 <dt>Uruguay</dt>
 <dd>The Oceanography, Hydrography, and Meteorology Service of the Uruguayan
 Navy (SOHMA) publishes an annual <a
-href="http://www.armada.gub.uy/sohma/index.php/servicios/datos-astronomicos" hreflang="es">almanac
+href="http://sohma.armada.mil.uy/index.php/servicios/datos-astronomicos" hreflang="es">almanac
 (in Spanish)</a>.</dd>
 </dl>
 </section>