[Dovecot] best way something thinks to upgrade dovecot to 1.2.* 2.0.*

[fakessh]

hello all
hello dovecot network
hello timo


What are your tips for successful migration for dovecot (atrpms , 
atrpms-testing depot for centos )
the page of wiki
http://wiki2.dovecot.org/Upgrading/2.0
explains the method to upgrade

I tried on my personal machine and the command cites wiki returns 
errors on the terminal
what to do with errors: correct the error in the configuration file ?

the question may seem simple but it is not pointless

many returns are welcome
something thinks are welcome

thanks