The Big Sur update to 11.4 is significantly smaller than that to 11.3, and its lists of changes are shorter. Apple reports that it adds Apple Podcast subscriptions and channels, and fixes bugs with bookmarks in Safari, the display of websites after waking from sleep, export of keywords of images in Photos, Preview freezing when searching PDF documents, and 16-inch MacBooks freezing when playing Civilization VI. Apple’s full listing is here, with details for enterprise users here.

A full listing of security fixes is available here. They include five kernel bugs, several which could enable apps to break out of their sandbox, a bug in kext management which could allow the loading of unsigned kernel extensions, no less then five vulnerabilities in smbx, and six in WebKit. Apple warns that one bug, which allows a malicious app to bypass Privacy settings, may already be actively exploited.

Looking in greater detail at what has actually changed, the AppleKextExcludeList kernel extension has been updated again, now to version 16.4.0. There are firmware updates for Apple Silicon Macs to bring iBoot to version 6723.120.36, and for T2 Macs to bring their firmware to 1554.120.19.0.0 (iBridge: 18.16.14663.0.0,0). I have updated those for SilentKnight, and in the latest listing of current firmware updates. Once I have a complete list of other Intel Mac firmware changes, I will update those as well.

Among the significant changes in version or build number in bundled apps are:

• App Store, incremented build number
• Find My, incremented build number
• Home, incremented build number
• Mail, incremented build number
• Maps, incremented build number
• Music, updated from version 1.1.4 to 1.1.5
• News, from version 6.3 to 6.4
• Photos, incremented build number
• Podcasts, incremented build number
• Preview, a small increment in build number
• Reminders, incremented build number
• Safari, from version 14.1 to 14.1.1, build 16611.2.7.1.4
• Stocks, incremented build number
• Bluetooth File Exchange, from version 8.0.4 to 8.0.5
• Migration Assistant, from version 11.3 to 11.4
• VoiceOver Utility, incremented build number.

Significant changes in /System/Library include:

• Bluetooth components, from version 8.0.4 to 8.0.5
• DiskImageMounter, from version 595.101.2 to 595.120.2
• Dock and its components, incremented build numbers
• Finder and its components, incremented build numbers
• Raw Camera, incremented build number
• ARDAgent, AppleVNCServer and Screensharing in RemoteManagement, incremented build numbers
• Siri, from version 201.4.11 to 3005.3.1
• Software Update, incremented build number
• Several AMD and Intel graphics kernel extensions
• AppleBluetoothRemote kernel extension, from version 69 to 70
• AppleGraphicsControl kernel extension, from version 6.2.9 to 6.3.3
• AppleStorageDrivers kernel extension, from version 511.101.1 to 511.120.2
• AppleTopCase kernel extension, from version 4040.11 to 4050.1
• AppleVPBootPolicy, a new kernel extension, version 1.0
• IOBluetoothFamily kernel extension, from version 8.0.4 to 8.0.5
• APFS components from version 1677.100.114 to 1677.120.9
• smbfs kernel extension and components, from version 3.5 to 3.6
• many public frameworks, including PDFKit and WebKit, have incremented build numbers
• many private frameworks also have incremented build numbers
• many components of Mail have incremented build numbers
• a new addition to private frameworks is the RecoveryOS framework
• many Safari and WebKit components have incremented build numbers.

If 11.3 was the most extensive of Big Sur updates so far, 11.4 seems to be attending to finer details, which can be every bit as important for users.