As described on the Classic Linux migration page
after your files are copied from the old servers into the OLD subdirectory on the new server, they may become out of date. Most importantly, new mail might have arrived for you on the old servers. If you simply ask, we can do a refresh, and bring OLD up to date. New files on the old servers then will appear in OLD, and file deletions done on the old servers (including deletions of mail) will be also reflected in OLD after a refresh.
There are about 3–4 days left before all the old servers go offline. Once they are gone, no true refresh will be possible. We have backups in the cloud but these will not be as fresh as files on the actual old servers.
So if you need a refresh of OLD, now is a good time to ask for one.