Hello, thanks a lot for the hint.
I understood I have to execute one of the commands described in http://docs.nethserver.org/en/v7/mail2.html. As I use pop3 connector I guess it is the part from “From POP3 connector module” - correct?
However, reading quickly the docs I could not find a hint if all email settings currently included will be preserved after upgrade to Mail2?
E.g. Smarthost settings, all Pop3 connector information, SMTP settings…
Will this be ensured?
I also use actually some tweaking of the postfix files via the e-smith system (e.g. sender dependent smart host (relay host) with multiple smarthosts and sender dependent authentication - BTW would be a nice feature to configure such topic directly in nethserver 
, some small other changes in postfix config). I understood postfix is still be used in Mail2 system, so I guess my tweaks should work also in Mail2 (as the the config files should be generated again via e-smith templates).
And to be honest I’m still hesitating starting the upgrade having read of some issues while upgrading to Mail2, e.g. https://community.nethserver.org/t/problems-with-mail2-update/10147. Hope they are solved
Thanks again…