This is a bugfix release. You do not need to update your filters from 4.3.0.

The maximum slug length for registering custom plugin messages has been reduced to 200 characters.

• Fix incorrect constant for disabling last messages (h/t @kermina).
• Fix false positive with blocking user enumeration when a Contributor tries to list posts by another user.
• Fix index issue with ancient versions of MySQL. Premium only
• Fix harmless warning with a defined but empty `WP_FAIL2BAN_PROXIES` (h/t @stevegrunwell).
• Backport new Block event class.
• Update Freemius library.