S4 Hana is the new software made by the SAP company, which is based on SAP FICO which is the legacy model which handles the financial transactions in a company and much more.
SAP FICO being the legacy module, it is not going anywhere. In India, SAP FICO is still the most desirable module and it will call for some time perhaps years for companies to shift from ECC to SAP S4 HANA platform. They require skilled(by which I mean extremely skilled) professionals who could help companies let this change happen in a consistent way and with no-data loss.
Yes, SAP is the new thing and the demand for SAP S4 HANA FInance consultant is going to rise in time tiol come but to become a SAP S4 HANA FINANCE consultant it is recommended to learn SAP FICO first because it would be easy to get familiar and skilled with S4 HANA finance fast.
So, if you are a person who is already into SAP FICO then you can move up in the ladder by learning and getting certified in SAP S4 HANA Finance.(But, you first must know SAP FICO).
In short SAP FICO Consultants will remain in demand.