The options are limited, but quite granular. You can even choose to strip or keep file attachments, set storage limits, archive length, which user folders to ignore or include, etc...
Server backups are another facet of this whole lie. I can believe that their rotations overwrote the backups from 2 years ago, that is completely feasible... but not the archive system.
It really isn't.
They fired the company providing the archive system a couple of months into this process. The entire situation was engineered to have the emails age off with no archive, local or server or tape. This was deliberate and directed from above.