A new tzdata upstream version has been released for Debian GNU/Linux 9 LTS to update the time zone and daylight-saving time data,

DLA 2424-1: tzdata new upstream version

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Debian LTS Advisory DLA-2424-1 debian-lts@lists.debian.org
  https://www.debian.org/lts/security/ Adrian Bunk
October 31, 2020   https://wiki.debian.org/LTS
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Package : tzdata
Version : 2020d-0+deb9u1

tzdata, the time zone and daylight-saving time data,
has been updated to the latest version.

- Revised predictions for Morocco's changes starting in 2023.
- Macquarie Island has stayed in sync with Tasmania since 2011.
- Casey, Antarctica is at +08 in winter and +11 in summer since 2018.
- Palestine ends DST earlier than predicted, on 2020-10-24.
- Fiji starts DST later than usual, on 2020-12-20.

For Debian 9 stretch, this problem has been fixed in version
2020d-0+deb9u1.

We recommend that you upgrade your tzdata packages.

Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be
found at:   https://wiki.debian.org/LTS