Found this browsing Github and as I didn't see it posted here (apologies if I missed it) thought it would be of interest. It's the Sequoa support announcement for OCLP 2.0 from Mykola Grymalyuk (khronokernel) himself:

Another year, another WWDC and macOS version. This time with macOS 15, Sequoia, and a surprising lack of dropped hardware compared to previous years 🎉.

As the OS has been in developer beta for a few weeks now, we've compiled a list of challenges the patcher will need to overcome for this fall. This list will likely expand as we determine more issues with older systems.

• Dropped Models
• T2 MacBook Air and OpenCorePkg Challenge
• Trackpad Support
• MacPro3,1 Dual Socket Support
• General patches needing updates:
  • Graphics:
    • Metal 31001
    • Metal 3802
    • Non-Metal
  • Wireless
  • T1 Chip
  • USB 1.1
• Overall timeline for support

Dropped Models

One of the most tame OS releases since macOS Catalina, currently only 2 Macs were dropped:

MacBookAir8,1: MacBook Air (Retina, 13-inch, 2018) MacBookAir8,2: MacBook Air (Retina, 13-inch, 2019) 

T2 MacBook Air and OpenCorePkg Challenge

The current biggest issue we face with supporting the MacBookAir8,x (2018/19) series is the T2 chip's lack of communication when booted through OpenCorePkg.

What happens when one of these units boots through OpenCorePkg is that AppleKeyStore.kext panics due to timeouts with the T2 chip:

"AppleKeyStore":3212:0: sks timeout strike 18 "AppleKeyStore":3212:0: sks timeout strike 19 "AppleKeyStore":3212:0: sks timeout strike 20 panic(cpu 0 caller 0xffffff801cd12509): "AppleSEPManager panic for "AppleKeyStore": sks request timeout" u/AppleSEPManagerIntel.cpp:809 

This affects not only macOS Sequoia, but macOS Ventura and Sonoma are confirmed to have the same issue. Thus an underlying problem with the MacBookAir8,x's firmware where it is not happy with OpenCorePkg.

We currently do not have any leads on what exactly breaks the T2.

• MacBookPro15,2, MacBookPro16,2 and Macmini8,1 do not exhibit these issues in local testing
• MacPro7,1 does seem to surprisingly based on reports: MacPro7,1 - OpenCorePkg
  • Notes from this report were unsuccessful locally: Cannot boot MacPro7,1 #1487

Trackpad Support

Certain Force Touch Trackpads lost support in macOS Sequoia, namely those used by unsupported Macs. The primary issue is simply the loss of identifiers to match onto older hardware.

For most hardware, this has been resolved with the following commit:

• efi_builder: Add SPI trackpad support to Sequoia (ea12d44)
  • MacBookAir8,x is assumed to be broken, however, due to T2 issues, we cannot verify.

MacPro3,1 Dual Socket Support

Currently on macOS Sequoia, MacPro3,1 (2008) fails to boot due to a CPU panic:

processor_boot(): missing for cpu 4 u/processor.c:876 

This is due to the dual socket nature of the machine, and likely some firmware/ACPI table incompatibility. Temporary solution is to use cpus=4 boot argument (limiting to single socket), proper solution is currently unknown.

General patches needing updates

The following patches have broken either partially or entirely. This will require additional work to properly identify issues and solutions:

• Graphics:
  • Metal 31001
    • Intel Broadwell and Skylake
    • AMD legacy GCN, and modern GCN on non-AVX2.0
  • Metal 3802
    • Intel Ivy Bridge and Haswell
    • Nvidia Kepler
  • Non-Metal
    • Intel Iron Lake and Sandy Bridge
    • AMD TeraScale
    • Nvidia Tesla and Web Drivers
• Wireless
• T1 Chip
• USB 1.1

Overall timeline for support

As with every year, we cannot promise when support with be added. However following previous years' predictions, we hope for winter 2024 with OpenCore Legacy Patcher v2.0.0.

Development has been going strong internally and we hope everyone's excited!

For those watching development closely, know there will be a lack of commits for the month of July. This is primarily due to some scheduled surgeries for myself, and other members will be focusing on their amazing research and patch development. Thus the Python patching frontend and likely PatcherSupportPkg will be quiet. We hope to resume commits in August!