Install/upgrdae script: error in configuring postfix main.cf

The default main.cf file contains

myhostname = server1.example.com mydestination = server1.example.com, localhost, localhost.localdomain

The mydestination should not create problems since it is extracted also from the database, but myhostname is used as sender SMTP in the email header and it can cause the mail to be dropped as spam by the destination server since such domain do not exist. The installation/update script should ask for it or take the domain name from the system