ANN Erlang 21.3 support is reaching end-of-life

[Michael Klishin]

Hi folks,

As you know, the RabbitMQ team has adopted an Erlang support policy that states that we support two
most recent major releases (in practice, the most recent minor release of each) with a three-month
transition period when a new major ships.

The most recent major to ship was Erlang 23 in early May 2020. After more than three months, Erlang 21.3
support will be discontinued later this week. We still plan to ship a 3.8.8 release that will support 21.3 but
after that, all testing on that version will be discontinued and eventually 3.8 and future 3.9 nodes will refuse
to start on Erlang 21.3.

For those looking to upgrade, Erlang 22.3 is a release supported by RabbitMQ versions starting with 3.7.15 (from May 2019).
However, there are no real reasons not to upgrade to 23.x for those that run compatible RabbitMQ versions.
The CPU quotas changes alone would make 23 the obvious choice for anyone running RabbitMQ in containers, for example [2].

If you have any questions about Erlang 21.3 support, you are welcome to ask them in this thread.

1. https://www.rabbitmq.com/which-erlang.html
2. http://blog.erlang.org/OTP-23-Highlights/