Use Hub deployment making development activities of OData and Gateway maintenance independent . In Hub you can change the netweaver version accordingly in front end 7.4 / 7.5 without disturbing backend .
Reference:
NetWeaver Hubs
- Gateway: OData V4 support and developer productivity enhancements
SAP NetWeaver 7.5 - One common foundation for SAP Business Suite and SAP S/4HANA, on-premise edition
Regards
Virinchy