Upgrading Open Core requires the replacement of files in the Open Core EFI and a modification of the Open Core config.plist. After modifying the Open Core config.plist, you'll run Open Core's ocvalidate to confirm your config.plist changes.
You can perform the OpenCore upgrade manually (which is my preference) or you can use OCAT (search for it).
Files to be upgraded when upgrading Open Core are:
- EFI/OC/Drivers/*.*
- EFI/OC/OpenCore.efi
- EFI/OC/Tools/*.*
- EFI/OC/config.plist
In addition to upgrading Open Core, there may be Acidanthera kext upgrades for the kexts located in
OCAT will upgrade these kexts as well. You can look
here to see which Acidanthera kexts have been upgraded. Note that OCLP intentionally does not upgrade AppleALC.kext for some Mac Models for compatibility reasons.
When you "Build and Install Open Core" with OCLP, you may lose Open Core and kext upgrades that you performed on your own (without OCLP) if OCLP has not yet upgraded OC and kexts.
EDIT: I recommend testing your new EFI on a bootable USB thumb drive before replacing the EFI on your SSD. After you confirm proper operation of your Mac with the new EFI, transfer your new EFI to your SSD.