Apple begins work on iOS 19 update codenamed ‘Luck’ and more
What are the code names for macOS 16 and watchOS 12?

The code names for macOS 16 and watchOS 12 are "Cheer" and "Nepali," respectively. These code names are used internally by Apple during the development process and may not necessarily reflect the final product names or features.
What is the code name for iOS 19?

The code name for iOS 19 is "Luck." Apple has formally begun work on this software update, along with macOS 16 ("Cheer"), watchOS 12 ("Nepali"), and visionOS 3 ("Discovery") for 2025's major operating systems2. Although it is too early to know what features these updates will bring, the company follows this schedule to develop next year's hardware products and have accompanying software for testing.
When did Apple start developing iOS 19?

Apple began developing iOS 19 in late June 2024, following the announcement of iOS 18 at WWDC. This is in line with their typical software development schedule, as they concurrently work on upcoming hardware products and their corresponding software systems.