Apple switched OS numbering from literal variations to a year-based naming/numbering scheme for all Apple OSes.
Apple modified its model numbering conference from model numbering with iOS 18 and iPadOS 18 to year-based versioning with iOS 26 and iPadOS 26. As defined on Wikipedia; daring emphasis is mine:
iOS 26 is the nineteenth and the present main launch of Apple’s iOS working system for the iPhone. It was introduced on June 9, 2025, on the 2025 Worldwide Builders Convention (WWDC), and launched on September 15, 2025.
It’s the direct successor to iOS 18; its model quantity was introduced ahead to 26 as Apple modified its model numbering conference for consistency throughout its working programs.
This transformation was executed throughout all Apple OSes as defined on Engadget (June 9, 2025); daring emphasis is mine:
As a part of an overhaul to its working programs, Apple is making one of the crucial vital adjustments ever to its OS branding, the corporate introduced at its WWDC 25 developer’s convention. Beginning in 2026, it would shift from the present model numbers (macOS 15, iOS 18, iPadOS 18.5, and so on.) to a year-based system throughout its complete OS lineup. As such, the names will change to iOS 26, iPadOS 26, MacOS Tahoe 26, WatchOS 26, TVOS 26, and VisionOS 26 and comply with that sample going ahead.
