How to edit system sounds?

Hi, all.

I have custom IVR sounds setup but I noticed if I dial an invalid extension a recording plays that says something about an invalid route. I found the recordings at /etc/var/lib/asterisk/sounds/en but I noticed there are tons of files there and recording all those would be nearly impossible.

However, the one that played can be recorded with no issue but I’m concerned about system updates overriding my custom recording.

How do we accomplish this safely?

Thanks!