What has changed in Monterey 12.3.1?

The update to bring Monterey to version 12.3.1 is very small, and close to the minimum update size.

Apple claims that it addresses two issues: for Mac mini 2018 systems, it ensures that a USB-C or Thunderbolt display used as a second display turns on properly, and it fixes an incompatibility between some Beats headphones and other Bluetooth devices such as game controllers, which could disconnect after playing audio through the headphones.

Additionally, this addresses two other issues. The first are those few MacBook Pro 2021 models which have been unable to update to 12.3; this update should enable them to update to 12.3.1 successfully. The other is a strange bug which caused flickering in half a dozen pixels on Thunderbolt or Cinema Displays when connected using a USB-C to TB adaptor, with an M1 Mac; that has now been fixed too.

I’m glad to hear that this apparently fixes the severe bug in AppleScript which caused open [file] to fail. However, it doesn’t fix or alter in any way the memory leak seen in the Finder’s Find feature, nor does it display charge levels during recharging of Apple wireless input devices.

There are two security fixes included in this update, detailed here. One affects AppleAVD, the other Intel Graphics Drivers. Apple remarks that it’s aware of reports that both vulnerabilities have been actively exploited. These make this an urgent update for all Monterey users.

iBridge firmware in T2 Macs is updated from 19.16.14242.0.0,0 to 19.16.14243.0.0,0, and iBoot in M1 series Macs from 7459.101.2 to 7459.101.3.

The only bundled app to show a changed version or build number is Safari, which has a small increment in build to version 15.4 (17613.

Changes in /System/Library are also extremely limited, the most significant being:

  • some AMD kernel extensions, which increase version number
  • AppleAVD kernel extension, which increases version from 559 to 560, consistent with the security release notes
  • AppleGraphicsControl kernel extension, which increases version from 6.5.4 to 6.5.7
  • some AppleIntel graphics kernel extensions, which increase version number, consistent with the security release notes
  • JavaScriptCore, WebKit and SafariServices frameworks, which increase build numbers.

Updated 0710 GMT 1 April 2022.