This is the basic sync APIs and foundations of a more comprehensive product. See this thread: http://aerogear-dev.1069024.n5.nabble.com/aerogear-dev-Sync-Day-3-Sync-takes-Manhattan-td6074.html for details.

Here is the useful bits from the email :

1. M1 - Basic revision Control, Data Model, Change Management, Server <->
   Client Contract

• We seem to be in agreement on a basic set of metadata to be kept for
  each object. [objectId, revision, object].
• We should have a basic server definition which supports CRUD and
  keeps our revision numbers in check. This may not be a server product
  but just a spec that can be implemented by anything at this point.
• We should have basic client code which keeps up with revisions, can
  check the server for new revisions, and alert the user if there is a
  sync conflict.