WordPress 6.4.2 was released December 6, 2023. This is a maintenance and security release. The main item in this release is a patch for a critical security vulnerability. You can get more details in the release post. Updating to 6.4.2 immediately is highly recommended for all WordPress users.
If you are on an Outcome Labs WordPress Care Plan, the update will be verified against your site and deployed within twenty four hours. Please contact the helpdesk if you have any questions or encounter issues.