Before installing S7 F Systems V6.4, the following must be present on the Engineering Station (ES): Delivery release: SIMATIC S7 F Systems V6.4 - ID - Support

Without a license, you can configure F-blocks and run simulations, but you cannot load the safety program into an F-CPU. The CPU will go into STOP mode with error “SFS 2: Missing Safety License.”

How to Download SIMATIC S7 F Systems V6.4 – Safety Engineering for S7-1200/1500