WordPress has released a new maintenance update today to WordPress core: version 4.9.4. Version 4.9.4 comes with minor fixes which the WordPress core team deemed impactful enough to warrant a release. This is a follow up to the brief release of 4.9.3 that introduced an edge case fatal error. This release includes the other bug fixes for 4.9.3.
For details on this release you may reference the official blog post on WordPress.org: https://wordpress.org/news/2018/02/wordpress-4-9-4-maintenance-release/
As with all maintenance related updates, WordPress has released patches for older functional versions as well. As a WP Engine customer, no action is required. Our team is already working to push out automatic updates to your site(s) to ensure they are in the next version. You will receive an email notification when the update has been completed. Our team is always attentive to our promise to provide a secure WordPress experience for all WP Engine customers.