==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release):
- Deployed with iRedMail Easy or the downloadable installer?
- Linux/BSD distribution name and version:
- Store mail accounts in which backend (LDAP/MySQL/PGSQL):
- Web server (Apache or Nginx):
- Manage mail accounts with iRedAdmin-Pro?
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

Using CentOS 7 with MySQL (MariaDB) on new versions. 

Some long time use on file system and decided to do new install and migration to new OS while forcing users into the file tree options vs the older just named directory for the user. 

In doing such there is creation of the file system upon login. In one of the "Maildir" directories are two files. 
  dovecot-uidvalidity
  dovecot-uidvalidity.5ebf07bf
What is the second file (dovecot-uidvalidity.5ebf07bf) and what is the significance?   Should it be deleted.

Regarding to the old users data... 
Can one just move the entire old "Maildir" into place over the newly created iRedMail installer "Maildir" directory?  For example, all the below sub-directories/files would be replaced being inside the Maildir directory. 

cur
dovecot-acl-list
dovecot.index.log
dovecot.mailbox.log
dovecot-uidlist
dovecot-uidvalidity
dovecot-uidvalidity.5ebf07bf
.Drafts
.Junk
new
.Sent
subscriptions
tmp
.Trash

Would this create any issues for the iRedMail or iRedAdmin software or any other issues (assuming vmail:vmail ownership)?