I could be wrong but I always imagined Apple's KB page on BootROM/SMC (firmware) existed for two reasons, So users could check they had the most up-to-date versions and, if not, upgrade where necessary; and, To allow users to see if their firmware had been "tampered" with. On checking today I found Apple is stating a latest-version on their page that is older than that on my MBA11" Should I be worried?
It's an interesting question. My 2013 macbook air also shows MBA61.0099.B22 for the bootrom and 2.13f15 for the SMC, both of which are later versions than the Apple page. Apple doesn't say that these are the latest versions on the page, so the intent is unknown. Googling for MBA61.0099.B22 shows plenty of other people with the same version so I wouldn't worry too much. It is still quite mysterious and deserving of an explanation. Linky to the apple page: https://support.apple.com/en-gb/HT201518 Info about your bootrom / SMC can be found in 'About This Mac / System Report / Hardware Overview' - click on the apple icon at the top left of your screen.
My 2013 11" MBA shows version Boot ROM Version MBA61.0099.B12. But I am still running 10.8.5 and haven't updated anything for awhile.
Hiya, thanks for that. Apple Support told me that Firmware is updated as part of the macOS upgrade process so mine reflects the Firmware applicable to v10.11.6 The version listed on the KB is the latest version applicable to the original OS supplied with the device, listed elsewhere as being from OS X 10.8.4 (12E3067) to OS X 10.9.2 (13C64) ... so anyone running up to 10.9.2 should be able to upgrade to the version listed on Apple's KB page. Anyone who's upgraded beyond that should use software restore to restore their OS if they have concerns. x-B22 & and xf143 are the current firmware versions for 10.11 & 10.12
Ah, mystery solved! I suspected it might be something like that. Thanks for chasing it up with Apple.