Don't ask me why, it didn't do any. Told me it would, then when I pressed confirm it told me something which sounded to me as : "FUCK YOU. NOT DOING SHIT ABOUT BACKUP."
That is because the autobackup is highly annoying, eats tons of wasted disk space and I thus disabled it. Standard protocol for me was "cp -a server/world backup/" and then update, resulting in always having an update. I copied the entire mod and config folder as well. If you want it enabled edit the launchwrapper line to remove the correct -D parameter.