What the macOS 26.3 RC Shows
The latest macOS 26.3 Release Candidate build contains internal references to two new SoC identifiers—T6051 and T6052—mapped to platform codes H17C and H17D. These identifiers follow Apple’s naming convention for its M‑series chips.
Decoding the New SoC IDs
Based on the historical pattern of SoC IDs and platform codes, the new identifiers likely correspond to:
- T6051 / H17C – Expected to be the upcoming M5 Max chip.
- T6052 / H17D – Expected to be the upcoming M5 Ultra chip.
What’s Missing?
The expected M5 Pro chip, which would presumably use the T6050/H17S identifiers, does not appear in the RC build. This omission could mean the Pro variant will arrive in a later update or is still under development.
Implications for New MacBook Pro Models
Bloomberg reports that the next MacBook Pro lineup is “slated for the macOS 26.3 software cycle.” If the RC build is the same as the final public release, the presence of M5 Max and Ultra identifiers suggests those models could launch alongside macOS 26.3.
About the Source
Marcus Mendes, a Brazilian tech podcaster and journalist who has covered Apple since 2012, provided the insights that surfaced in MacRumors.