[[breaking-changes-7.7]]

=== Breaking changes in 7.7
++++
<titleabbrev>7.7</titleabbrev>
++++

{see-relnotes}

//NOTE: The notable-breaking-changes tagged regions are re-used in the
//Installation and Upgrade Guide

//tag::notable-breaking-changes[]

[float]
====  Environment variables can no longer reference other environment variables

Environment variables are still supported in the {beats} configuration.
However, starting in Version 7.7.0, an environment variable cannot reference
another environment variable or event in the configuration.

For example, if you have `export VAR1=${VAR2}` and use `var: ${VAR1}` in
the configuration, this results in `var: "${VAR2}"`, where
`${VAR2}` is not expanded.

[float]
==== Docker and kubernetes processors no longer allowed in script processor

Prior to this release, it was possible to use the `add_docker_metadata` and
`add_kubernetes_metadata` processors in the `script` processor. This was not a
good practice because it sometimes resulted in memory and file descriptor leaks.

Starting in version 7.7.0, scripts that use these processors will fail. To
resolve this problem, define the processors in your configuration instead of the
script.

[float]
==== Known issue with Kafka output

The Kafka output fails to connect when using multiple TLS brokers. We advise
not to upgrade to {beats} 7.7.1 if you're using the Kafka output in this
configuration.

[float]
==== Systemd unit file no longer overrides logging options

Prior to this release, the systemd unit file set `BEAT_LOG_OPTS=-e`, which
caused {beats} to ignore the logging options specified in the
configuration file.

The systemd unit file no longer sets this option, and the logging settings
specified under `logging` in the configuration now work.

If you set `Environment="BEAT_LOG_OPTS=` in a previous release to work around
this problem, remove that workaround now, and use the `logging` options in the
configuration file to control logging behavior. For example, see
{filebeat-ref}/configuration-logging.html[Configure logging]. 

// end::notable-breaking-changes[]
