Updating system with iRedMail

==== Required information ====
- iRedMail version: Latest
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): LDAP
- Linux/BSD distribution name and version: Deb7
- Related log if you're reporting an issue:
====

Hi!

On iRedMail system, is it safe to run 'apt-get update' 'apt-get upgrade --show-upgraded'?

What will happen if I execute the above sequence, and then update iRedMail from 0.8.6->0.8.7 (in that order)?

Thanks Zhang for best open source mail sln on the net.