In addition to the changes needed to support Subscriptions with Submarine, Memberships require a metafield to be added.
In the Shopify Admin, Membership products are identified by the presence of a
_membership_duration variant metafield, i.e.
3_months. Note that this frequency must match the subscription frequency set by the source Shopify order (as per regular subscriptions) or a membership subscription will not be created.
You can read more general information on Memberships here.
Updated about 1 year ago