[Dovecot] upgrade from 1.0.5 to 2.1.7

[Andreas Meyer]

Hello!

I want to upgrade the docevot-installation from v 1.0.5 to 2.1..7

Now I get the following executing
doveconf -n -c /etc/dovecot/dovecot.conf > /home/mail1/dovecot-2.conf

doveconf: Warning: Obsolete setting in /etc/dovecot/dovecot.conf:217: add auth_ 
prefix to all settings inside auth {} and remove the auth {} section completely
doveconf: Warning: Obsolete setting in /etc/dovecot/dovecot.conf:219: passdb 
passwd-file {} has been replaced by passdb { driver=passwd-file }
doveconf: Warning: Obsolete setting in /etc/dovecot/dovecot.conf:222: userdb 
passwd-file {} has been replaced by userdb { driver=passwd-file }

The section  at line 217 looks like this:

auth default {
  mechanisms = plain
  passdb passwd-file {
  args = /etc/dovecot/passwd
  }
  userdb passwd-file {
  args = /etc/dovecot/passwd
  }

How do I change it to fullfill the new needs?

And how do I handle line 217?
add auth_ prefix to all settings inside auth {} and remove the auth {} section 
completely
?

Thanks for help!

 Andreas