FIAAS currently uses extensions/v1beta1 Ingress. This API will be disabled in Kubernetes 1.20. networking.k8s.io/v1beta1 Ingress which is supposed to replace this API is available in Kubernetes 1.14 and later.
networking.k8s.io/v1 Ingress is GA in Kubernetes 1.19, and according to the changelog it looks like the plan is to remove extensions/v1beta Ingress in Kubernetes 1.22 (or later?).
FIAAS currently uses extensions/v1beta1 Ingress. This API will be disabled in Kubernetes 1.20. networking.k8s.io/v1beta1 Ingress which is supposed to replace this API is available in Kubernetes 1.14 and later.