[ANNOUNCE] Apache ZooKeeper 3.5 End-of-Life 1st June, 2022

[Andor Molnar <an...@apache.org>]

Hi,

The Apache ZooKeeper community would like to make the official announcement of
3.5 release line End-of-Life. It will be effective on 1st of June, 2022 00:01 AM
(PDT). From that day forward the 3.5 version of Apache ZooKeeper won’t be
supported by the community which means we won’t 

- accept patches on the 3.5.x branch,
- run automated tests on any JDK version,
- create new releases from 3.5.x branch,
- resolve security issues, CVEs or critical bugs.

Latest released version of Apache ZooKeeper 3.5 (currently 3.5.9) will be
available on the download page for another year (until 1st of June, 2023), after
that it will be accessible among other historical versions from Apache Archives.

=== Upgrade ===

We recommend users of Apache ZooKeeper 3.5 to plan your production upgrades
according to the following supported upgrade path:

1) Upgrade to latest 3.5.x version 
2) Upgrade to latest 3.6.x version
3) (Optional) Upgrade to latest 3.7.x version.

Please find known upgrade issues and workarounds on the following wiki page:
https://cwiki.apache.org/confluence/display/ZOOKEEPER/Upgrade+FAQ

In addition to that the user@ mailing list is open 24/7 to help and answer your
questions as usual.

=== Compatibility ===

Our backward compatibility rules still apply and can be found here:
https://cwiki.apache.org/confluence/display/ZOOKEEPER/ReleaseManagement

Following the recommended upgrade path with rolling upgrade process ZooKeeper
quorum will be available at all times as long as clients are not starting to use
new features.

Best Regards,

-Andor