You are looking at preliminary documentation for a future release. Not what you want? See the current release documentation.
As a general rule, you can upgrade between minor versions (for example, 8.x to 8.y, where x < y) by simply installing the new release and restarting Logstash. Logstash typically maintains backwards compatibility for configuration settings and exported fields. Please review the release notes for potential exceptions.
Upgrading between non-consecutive major versions (6.x to 8.x, for example) is not supported.
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