Upgrade Error

At the tail end of upgrading Webmin and Usermin to the latest version, I received the following error message.

Require postfix/postfix-lib.pl failed :

Undefined subroutine &postfix::compare_version_numbers called at /usr/libexec/webmin/postfix/postfix-lib.pl line 37.

Webmin: 1.840-1 / Usermin: 1.710-1



Looks like this can happen if during the upgrade there is a mix of old and new Webmin code running. It's pretty harmless though, and won't happen in future upgrades.