Upgrade path from v1 addon

Is the upgrade path for existing v1 addons created with default Ember CLI addon blueprints defined already? Or should we hold back migrating existing addons still for some time?

I'm primarily interested in migrating addons to v2 format which aren't that actively maintained. This is not an early adopter case. Churn should be minimized. But I hope that after all experiments with `@embroider/addon-blueprint` this new blueprint is now stable. Is that expectation correct?