Can free5GC work with 4G eNodeB?

When we released stage 1 of free5GC (v1.0), we kept the S1AP interface to 4G eNB. We tested free5GC with some commercial eNBs successfully.

Our stage 2 (v2.0) and stage 3 (v3.0) implementations of free5GC follow the 3GPP R15 standalone (SA) standards. Therefore, they cannot work with 4G eNB.