RabbitMQ `3.10.8` is a maintenance release in the `3.10.x` release series.
Please refer to the upgrade section from [v3.10.0 release notes](https://github.com/rabbitmq/rabbitmq-server/releases/tag/v3.10.0)
if upgrading from a version prior to 3.10.0.
This release requires Erlang 24.2 and supports Erlang 25.
[RabbitMQ and Erlang/OTP Compatibility Matrix](https://www.rabbitmq.com/which-erlang.html) has more details on
Erlang version requirements for RabbitMQ.
### Minimum Supported Erlang Version
Erlang 23 support has reached its [end of support](https://www.rabbitmq.com/which-erlang.html).
Starting with this release, RabbitMQ requires Erlang 24.2 or later versions. Nodes **will fail to start** on older Erlang releases.
Erlang 25 as our new baseline means much improved performance on ARM64 architectures, [profiling with flame graphs](https://blog.rabbitmq.com/posts/2022/05/flame-graphs/)
across all architectures, and the most recent TLS 1.3 implementation available to all RabbitMQ 3.11 users.
### Open File Handle Limit is Capped by Default on Linux, *BSD, macOS
Nodes now default to 65536 concurrent client connections instead of using the effective kernel open file handle limit.
Users who want to override this default, that is, have nodes that should support more concurrent connections and open files,
now have to perform an additional configuration step:
* Pick a new limit value they would like to use, for instance, 100K
* Set the maximum open file handle limit (for example, via `systemd` or similar tooling) for the OS user used by RabbitMQ to 100K
* Set the [`ERL_MAX_PORTS` environment variable](https://www.rabbitmq.com/configure.html#customise-environment) to 100K
This change was introduced because of a change in several Linux distributions: they now use a default open file handle limit so high,
they cause a significant (say, 1.5 GiB) memory preallocated the Erlang runtime.
The new default [comes from modern systemd](https://github.com/systemd/systemd/commit/a8b627aaed409a15260c25988970c795bf963812).
See [rabbitmq/rabbitmq-server#5684](https://github.com/rabbitmq/rabbitmq-server/pull/5684) and [docker-library/rabbitmq#545](https://github.com/docker-library/rabbitmq/issues/545#issuecomment-1224977154)
for details.
## Changes Worth Mentioning
Release notes can be found on GitHub at [rabbitmq-server/release-notes](https://github.com/rabbitmq/rabbitmq-server/tree/v3.10.x/release-notes).
### Core Server
#### Enhancements
* When a virtual host is added, it now can be configured with default queue type.
