Earlier today, Apple rolled out the Release Candidates for iOS 26.3, macOS 26.3, and other platforms of version 26.3. Perhaps unsurprisingly, these soon-to-be-released versions could reveal several more details about Apple’s unreleased products, and today’s release to developers is no exception.
Apparently, Nicolás Alvarez, who has spotted several code references on future Apple products in the past, has shared some details he discovered with MacRumors. The iOS 26.3 RC references two unreleased system-on-a-chips: T6051 and T6052, which have the platform names H17C and H17D, respectively. What do these codenames mean? We’ll break it down for you. The number 17 refers to the M5 generation of chips; as a matter of fact, the M5 base 14-inch MacBook Pro has the model identifier “Mac17,2”. So we know for sure that all incoming Macs with any chip in the M5 family will be in the same family of model identifiers, i.e., it will have a model identifier “Mac17,x.”
Additionally, Apple consistently uses lettering to reference the “tier” of the M-series chip:
- “G” is used for the base (M-series) chips.
- “S” is used for the Pro chips.
- “C” is used for the Max chips.
- “D” is used for the Ultra chips.
If we put two and two together, this means that we could see the M5 Max and the M5 Ultra chip in the coming months. Interestingly, the RC does not have any references to the T6050 H17S, which could be the chip identifier and platform name for the M5 Pro chip. It’s still possible that the M5 Pro chip is coming; the code for iOS 26.3 has not referenced that chip yet. Nevertheless, I’d bet that upcoming MacBook Pros will be coming out as soon as next week, and they’ll still feature the M5 Pro and M5 Max. We should see an update to the Mac mini with the M5/M5 Pro chip as well as the Mac Studio with the M5 Max/M5 Ultra chip in a few months, possibly at WWDC.
We’re seeing a dwindling supply of the higher-end MacBook Pros with the M4 Pro/M4 Max chips, so we likely won’t have to wait too long for Apple to update its pro laptop.
Just for a bit of trivia, here are all the platform names for every M-series chip that Apple released to date:
| M1 | M2 | M3 | M4 | M5 | |
| “Base” | H13G | H14G | H15G | H16G | H17G |
| Pro | H13S | H14S | H15S | H16S | – |
| Max | H13C | H14C | H15C/H15M | H16C | – |
| Ultra | H13D | H14D | H15D | – | – |
As you can see, the “H13” in the platform name refers to any M1-series chip, “H14” M2-series chip, “H15” M3-series chip, and so on. Interestingly, Apple used the M variant for the M3 Max (14-core), whereas the C variant is used for the 16-core chip.
