[Dbmail] Upgrade?!

[sl]

Well, since 2.2 is considered stable and 2.0 ist "old stable" id like to
know what is the upgrade process for live systems?!
The "documentation" has no sections about this.
 
SO!
 
what to do for upgrading from 2.0.10 to 2.2.0?!
any risky cliffs?! maybe adding an upgrade instruction set to the readme or
install file of the distribution archive?!
 
regards
 
Simon