How do unsubscribes integrate between v1 and v2/3?
On a high level, the way it works is that v1 unsubscribes get imported into v2/3 but not vice versa.
The reason we've gone that route is because for most customers that logic has made sense. If someone unsubscribes from a triggered email (v1), we want to avoid sending them newsletters (v2/3) because in general triggered emails are more personalized than newsletters.
So if they don't want a triggered email, there's a good chance they definitely don't want a newsletter.
So if you export your unsubscribes from v1 and notice that you have less than the number of unsubscribes in v2/3, that would usually be normal.
If you are interested in syncing the unsubscribes both ways, that's a setting that can be enabled on your account - just get in touch.