*) Backup old Dovecot config files before you go further.
*) Install a Debian 7 virtual machine with Xen/KVM/VMware, then you get a Dovecot-2 config file for Debian 7. If you didn't modify Dovecot settings under Debian 6, you can simply copy the new config file.
Reference: http://www.iredmail.org/forum/topic4493 … tos-5.html