Expose Versions Property of SPListitem objects in CSOM/REST
On the server side it is easy to get older versions of a list item by using the Versions property of the list item object. Please add the ability to retrieve this property of list items via the client side object model and/or the SharePoint REST api.
Jim How commented
When will this api be made available? It's preventing our solution from being 100% functional for our customers using SP Online.