WP-CLI v0.23.1 is a compatibility release for those who’ve installed WP-CLI with Composer and require a minimum-stability. See #2664 for related conversation.
If you’re using the Phar distribution of WP-CLI, you should wp cli update, but don’t need to prioritize it, as the release doesn’t change WP-CLI’s behavior in any significant way.
Contributors to this release: danielbachhuber
You can browse the full list of resolved issues on GitHub.