iOS 27.3 will expand new StandBy features first introduced on the iPhone Duo to all iPhone models compatible with the update, according to Apple.

StandBy iOS 17
StandBy mode makes it easier to view information at a glance while your iPhone is placed on a charger and in a landscape position. It effectively turns an iPhone into a bedside clock with some extra details. On the iPhone Duo, StandBy also works when the device is folded like a book or a tent, even when it is not charging.

StandBy iOS 17

The new StandBy features coming to the iPhone 11 and newer:

iOS 27.3 also introduces vertical tabs in Safari, reintroduces Apple's redesigned Health app, enables some Apple Intelligence features in China, and more.

iPhone Duo StandBy Weather
iPhone Duo StandBy Calendar
The first iOS 27.3 developer beta was released earlier today, and Apple said the update will be released to the public in December.