Enketo offers different views of the same webform some online-only and some offline-capable. It's up to the data/form server that integrates with Enketo to decide which of these they expose to users (and how to make this clear to users). So e.g. KoBoToolbox.org and Ona.io have used these since the beginning, but e.g ODK Central has not yet done this (though to be added soon maybe?). ODK Aggregate can be configured to use either online-only or offline-capable views.
If you're using ODK Aggregate use /api/v1 instead of /api/v2 in the Enketo settings in Aggregate.
I hope this helps,