Long-term vise I think this is a dubious solution to "set up and forget", or advise people with few resources or limited Linux skills to use.

Mail in a Box makes it seem passably easy to someone with basic skills to get everything up and running, but then don't support in-place upgrades of the underlying operating system. This might be fine, but I really hope people realize what they're getting themselves into. https://discourse.mailinabox.email/t/mail-in-a-box-version-v...

This critique is somewhat shallow, if the backup/restore option is easy enough. But I just have a hunch there's going to be a lot of non-upgraded boxes running fullstack-EOL everything.

Of course, a system that does in-place upgrades and then fails is going to leave no-one any happier either.

I guess that my point really is that appliances requiring "complicated" upgrades by moving to a new OS install aren't all that mature. But I acknowledge I have a hard time determining who this product really is for.