There are no plans to produce 64bit versions of the legacy APIS such as SFC.
Clients should be encouraged to migrate to easy to use EMA which is part of the Refinitiv Real-Time SDK.
Other alternatives they can consider include the Websocket API and the Refinitiv Dataplatform Libraries too.
EMA is Elektron Message API and it is almost as easy to use as SFC and has additional benefit of natively supporting the cloud infrastructure. Here are the tutorials and samples for the C++ version of EMA. You can also download the SDK from the downloads page.