Let me share my understanding:
- Is it possible to implement delta support without shared data? >> yes very much
2.Delta token is dependent of the structure of your API? for example XML or JSON >> If your OData producer is SAP Gateway then you will get deltas through XML
(SMP supports both JSON/XML)
I have written a blog Run your mobile app in offline and best practices-openSAP-Developing mobile apps with HCP-Week 5 that has some info on delta token.
Regards,
JK