linux - Debian: updating package lists with apt-offline, --simulate not understood for apt-get update

I can't use apt-offline to update my package lists, which means that I will get many 404s when trying to install older versions of packages that it thinks it's downloading from the .sig file it generates. I can apt-get --simulate install or upgrade, but I can't simulate update (as in package lists), and it says "E: command line option --simulate is not understood." On my Ubuntu machine (connected to the internet) I can apt-get --simulate update just fine and it will simulate an update on any account.