macOS 27 “Golden Gate” removes the client support needed for AirPort Time Capsule backups, ending out-of-the-box compatibility with Apple’s Time Capsule models as the operating system no longer supports the legacy file-sharing protocols they rely on. Time Capsule was introduced in 2008 and was designed to work with Time Machine using network storage. Over time, Apple phased out the older networking stack: AFP support is deprecated and removed from newer macOS releases, and macOS 27 is described as requiring newer SMB versions and stricter security settings that typical Time Capsule hardware cannot meet.
Because Time Capsules traditionally depend on AFP and SMBv1, users updating to macOS 27 will need an alternative backup destination. One response highlighted across reports is a community project called TimeCapsuleSMB, created by James Chang, a Microsoft engineer. The project installs a modern Samba build directly onto a Time Capsule so it can advertise over Bonjour and accept authenticated SMB3 connections, letting macOS 27 treat the device as a current SMB backup destination.
The project is free and documented publicly. Reports note practical differences by model: some Time Capsule generations restart the Samba service automatically, while older units require a manual activation after reboot. macOS 27 is currently in developer beta, with a public beta expected later and a general release planned for September.