The update bringing macOS Tahoe to version 26.5 is modest in size and, apart from its security fixes, seems largely routine maintenance.

The only release notes worth reading are those listing vulnerabilities fixed, available here. Among the 69 listed there are 9 in the kernel, which must be the highest number in any recent macOS update. I wonder whether those have been swelled by AI, and one of the kernel bugs is credited to a researcher “with Claude and Anthropic Research”. There could of course be fixes resulting from early use of Mythos, but they’re unlikely to appear in a public list. None of the fixes listed are reported as being known to exist in the wild.

The new build number for 26.5 is 25F71. Apple silicon Macs have a firmware update bringing them to mBoot 18000.120.36, and Intel Macs with T2 chips are updated to 2103.100.6.0.0 (iBridge 23.16.15067.0.0,0).

Bundled apps have routine increments in version numbers:

• Books, from version 8.4 to 8.5
• Freeform, 4.4 to 4.5
• Music, 1.6.4 to 1.6.5
• News, 11.4 to 11.5
• Passwords, 2.4 to 2.5
• Safari, 26.4 (21624.1.16.11.4) to 26.5 (21624.2.5.11.4)
• Stocks, 8.4 to 8.5
• TV, 1.6.4 to 1.6.5.

Although there are abundant increments in build numbers reflecting routine maintenance, there are few substantial changes apparent in /System/Library, including:

• In kernel extensions, the whole AGX series has a substantial change in version, as does AppleUSBAudio, and smbfs is updated to version 6.0.1
• APFS is incremented to version 2811.120.14
• There’s a new AppleAccountTransparency in private frameworks.