Last Monday wanted to use Rig Manager and go through my rigs. I started it up and it said there was a new version to download and install, so I did so. Then when I connected it to my Powerhead, which was running last version of 2.3 FW, it would not work said I needed latest version. Didn't want to get into that at the time, so just disconnected and went through them by hand. Didn't think anything of it.
Then, yesterday evening went to rehearsal, set up my rig, started the Kemper, it started to boot then stopped and said it was trying to boot and burn FW from the USB port. Uh oh, what the heck... 
Power cycled it, no change, it wanted new FW. So, I used my band-mate's PC to download the 2.4.2 FW and extracted the kaos.bin and put it on a thumbdrive and installed it, took a while, but it worked and I was up and running. At the time was a bit unhappy about the problem, but now am just letting you folks know what happened to me and what to do.
I am now running the beta version and hoping like crazy it doesn't develop some goofy unsolvable bug while on stage. 
And, since this occurred, just in case, gotta bring my backup rig (Crate PowerBlock + Zoom GX3 + Fulltone Plimsoul) to rehearsals, too. Once bitten, twice shy. Caveat emptor! 