I am trying to migrate all of my users from one server to another, now i don't have many websites (5 of them) so it's not an issue to go manually, when i create account to second server i add user, configure everything as it was on first server and get passwords from database. But mail folders are confusing me a bit, they are different so i don't know what should i copy, and what to keep on new server. There are few files with dovecot index, keyword, idlist, subs, and so on... Some of these files don't exist on new server but .sieve file do exist, so i don't know is it safe to overwrite and delete, or need to keep those files on new server not overwritten. Here is a look on one maildir folder.