No updates for Intel Macs without T2 chips, apart from the iMac19,1, and there only in Sonoma. T2 and Apple silicon models are more confusing, though.
T2
This article lists the firmware versions of Macs that have been successfully upgraded to run macOS 14.8.2 Sonoma. […]
First added to Macs in the T1 chip, the Secure Enclave makes it far harder for an attacker to gain access to secrets like the FileVault encryption key.
Although your Mac may be unable to boot into macOS, it might be able to start up in Recovery, or offer its internal SSD in Target Disk Mode.
Provenance, condition, AppleCare, Activation Lock, and finally Handover – steps to ensure your money is well spent and you don’t get buyer’s remorse.
Do you need to back it up when the problem is minor? Should you erase its internal storage? Anything else you need to do?
Still very useful procedures for Intel Macs, resetting the SMC within a T2 chip is more complex. Used wisely they can resuscitate a failing Mac.
Is your Mac likely to receive firmware updates in future? How can you check whether its firmware is up to date? What happens in Sonoma?
Why do macOS updates keep updating firmware? Is it full of bugs or what? And just what does firmware do?
When should you put your Mac into DFU mode, hook it up to another Mac running Configurator, and revive or restore it?
The Eclectic Light Company 