As of today, Apple has published macOS Big Sur 11.6.4, a security patch update for Mac customers who choose to keep using the Big Sur operating system rather than the newer macOS Monterey.
All eligible Macs may download the macOS Big Sur 11.6.4 update from the Software Update preference pane in System Preferences.
Two weeks ago, macOS Big Sur 11.6.3 was issued together with macOS Monterey 12.2, and today’s upgrade is in response. Normally, new versions of macOS Big Sur are released in conjunction with Monterey upgrades, but today’s Big Sur software release is separate from them.
Big Sur 11.6.4 “enhances macOS’s security,” according to the release notes, and is recommended for all users.
A 2022-002 macOS Catalina security patch has also been provided by Apple for people who are still using Catalina.