Upon upgrading a nospam type server last week, the amavisd decided to not send any mail anywhere. Looking through the mail logs, it became apparent that amavisd did not know about an attribute that Postfix is using called smtputf8. With Postfix 3.0, the attribute is now on by default. In order for the (not yet patched) amavisd to work with this, you will need to disable it in postfix config by adding “smtputf8_enable = no” to the configuration and then reloading the config (or running postfconf “smtputf8_enable = no”). See the postfix section on smtputf8 for more details.