Apple released the final version of iOS 27.1 this week, but it is only available for the foldable iPhone Duo that launched today. iPhone Duo already ships with iOS 27.1 preinstalled, but users need to update to a newer build of iOS 27.1 during setup, available for download as an IPSW file as of Thursday. Apple's release notes for the newer build only mention unspecified "bug fixes for your iPhone." iOS 27.1 has no security fixes.
Apple jumped ahead to an iOS 27.2 beta for all other compatible iPhone models, and the iOS 27.2 Release Candidate is compatible with the iPhone Duo too, so all models will upgrade to iOS 27.2 for consistency. iOS 27.1 was likely kept exclusive to the iPhone Duo to prevent Duo-specific software features from leaking before launch.
iOS 27.2 is expected to be released next week. Apple retail staff have been warned that walk-in purchases of the iPhone Duo may not be possible on launch day due to anticipated stock shortages.
Source: MacRumors · Summarized by HeadlinesBriefing