Apple’s yet-to-be-released chips are referenced in the iOS 26.3 RC build.
The iOS 26.3 release candidate build has been found to contain identifiers for two unreleased Apple chips, which could be the M5 Max and the M5 Ultra.
On Wednesday, a week after the release of the third developer beta, Apple deployed a version of the iOS 26.3 release candidate. While the update itself doesn’t appear to include any new features, the software does contain files that point to Apple’s unannounced processor.
Since macOS 26.3 is tied to upcoming MacBook Pro models, as he pointed out AppleInsider in 2025, it’s no wonder that iOS 26.3 RC contains mentions of the M5 Max chip. The code also points to what appears to be the M5 Ultra, a chip that could debut with the Mac Studio upgrade.
Ace MacRumors points out that the iOS 26.3 RC build mentions the T6051 chip, also referred to as the H17C. There is also a T6052 system-on-chip, known as H17D in code.
Based on Apple’s existing naming patterns, the H17C chip is expected to be the M5 Max. Apple used the letter “C” for its past “Max” chips such as the M1 Max (H13C) and M4 Max (H16C).
The chip labeled H17D, meanwhile, could be the M5 Ultra chip, as all the M1 Ultra to M3 Ultra chips used the “D” naming scheme.
Interestingly, iOS 26.3 RC does not contain any references to the T6050 or H17S chip, which is the expected chip identifier for the M5 Pro. It’s unclear if Apple has changed its internal naming system for the M5 chip family, but it’s possible.
In any case, upgraded MacBook Pro models with new chips are expected to debut with macOS 26.3 in February or March 2026,