If you upgrade your door and then go outside and add a new secondary code, it will not work until you downgrade the door and upgrade the door again (additional cost). The upgrade command will remind you of this.
For those of you who already have doors with secondary codes who want to take advantage of this, you'll have to downgrade your door and upgrade it again for this new code to work.
As this is new, please offer your feedback and report any issues! If you do encounter an issue, please xhelp and don't take undue advantage of that issue.