>> Do we need to migrated to S4 hana
No. Don't be confused between Hana & S4H. HANA is a DB where as S4H is a business suite only on Hana.(AFAIK)
Have a look at the below links:
FAQ - System Copy and Migration
Migration of SAP Systems to SAP HANA
Frequently Asked Questions | SAP Support Portal
https://websmp104.sap-ag.de/~sapidb/011000358700000950402013E
regards,
pavan