Been running this on a duo v1 and it remembers that the duo is connected to the vault account when you look at the duo web admin pages.
On the duo V2 - you put in your vault account/password and link it - it then says you have linked your account.
You can then click on the link to create/amend your backups. (again logging in)
What I find perplexing/annoying.
If I come out of the dashboard for the duo v2 and then go back in again - when i look at the vault settings - its says its linked BUT the account information is blank. I have to re-enter this each time. Surely (just like on the duo v1) it should remember this once entered? After all, if you want to maintain the backups you still have to login to the vault maintenance web page seperately.
Just an annoyance