Apple's OS 27 public beta 4 ships on the same build as developer beta 6

Apple released the fourth public betas of iOS 27, iPadOS 27, tvOS 27 and macOS 27 Golden Gate on August 17, a few hours after seeding the sixth developer betas of the same train ^[1][2]. For anyone shipping an app against these OSes, the detail that matters is not the wallpaper: each public beta carries the same build number as its matching developer beta 6 ^[10], so the widest tester pool Apple has is now running exactly the code developers are running ^[13].

The strings, per 9to5Mac: iOS 27 and iPadOS 27 public beta 4 are 24A5418b, macOS 27 is 26A5416a, and tvOS 27 is 24J5353b ^[11]. Note that macOS carries a 26A prefix while iOS and iPadOS carry 24A and tvOS carries 24J ^[16]. Anything in your crash grouping, analytics buckets or MDM rules that parses build strings should be checked against all four rather than pattern-matched off the iOS shape.

The change lists are the real signal. MacRumors reports that few new features were found in the developer betas, with macOS Golden Gate getting new wallpapers and iOS 27 getting a Shortcuts splash screen and a new Game Center icon, and says the beta testing process is nearing its end ^[3][4]. 9to5Mac's list is of a similar weight: a new macOS wallpaper and redesigned stoplight window controls, an updated iOS notification animation, and an updated Preview icon on the Mac matching the iOS version from the previous week ^[5]. The same report says the pinned Messages interface bug introduced in beta 5 appears to be resolved in beta 6 ^[12]. When the notable diffs are icons, an animation and one regression closed out, the feature surface is frozen in practice and the remaining seeds are cost of goods on bug fixing.

On cadence, MacRumors says public beta 4 arrived a week after public beta 3 ^[6]. If that weekly rhythm holds, the next public seed lands around August 24 ^[17]. 9to5Mac describes the official release as a few weeks out ^[7]. Neither report mentions a release candidate build, so treat the RC date as unscheduled rather than imminent ^[14]. Also worth keeping straight internally: the public track is numbered 4 while the developer track is numbered 6, which will cause confusion in bug reports unless your intake asks for a build string instead of a beta number ^[15].

What to watch: whether the pinned Messages fix survives the next seed, since a regression that reappears after a claimed fix is the kind of thing that pushes an RC ^[12]; whether the build strings keep moving while the feature notes stay empty, which is the usual shape of the final stretch ^[3][4]; and how many of your own inbound reports now come from public testers who cannot roll back easily. Apple still recommends installing beta software on a secondary device, and taking a recent backup if you use your primary iPhone ^[8]. Enrollment runs through beta.apple.com and then Settings, General, Software Update, Beta Updates ^[9]. That guidance is a reasonable reminder that public beta 4 is not a fleet policy, however close the release feels.