Yes we are considering v2 out of beta, and the preferred API to use going forward. We are relying on v2 for a lot of website functionality, and for most API usage for the latest iOS iNaturalist app. We have not officially deprecated v1 yet, though that might make sense for us to make a statement to that effect to make it clear it is preferred to use v2 over v1. We have updated documentation on the very old website-based API to consider all methods deprecated aside from the authentication-based methods.
The fact is some of our “classic” mobile apps use v1 heavily, so it will not be practical for us to disable it anytime soon. So there’s no immediate need to migrate away from v1 yet. We’ll be sure to make public announcements if we set a timeline for when v1 will no longer be available.
I would recommend using v2 for new work. As for migrating from v1 to v2, I’d say it will be quite a while (at least a year?) until we would be able to disable v1. My preference would be to give at least several months heads up to API users before we do that so API users are not left scrambling to schedule time for updates.