After each of the last two Virtualmin updates, one of my clients has lost the following two links from his menu:
Edit Mail and FTP Users
Edit Mail Aliases
I found that if I go to the "Edit Owner Limits" page, under "Edit capabilities for virtual servers", I had to reselect the following two options:
Can manage users
Can manage aliases
Basically, it looks like a lot of the settings on this page were reset back to the defaults during the Virtualmin upgrades, but this only happened to affect one of my clients, even though everyone else is fine.