When the retirement of the Sync API (and the turning off of API V1) was announced I recall there being a post from a Dropbox team member saying not to worry and you would be able to implement syncing using API V2. To facilitate this it was stated that examples would be provided to help out Dropbox Sync users with code examples, blogs and so on.
I can't see that anything like this has appeared. Is there any documentation anywhere which will help people transition from the Dropbox Sync API to something equivalent using the Core API 2?