SRv6 Capable NOS and Devices

I know the SRv6 is a fairly new technology. I am wondering which vendors and network operating systems fully support SRv6 today? Has anyone deployed this new technology? If building a greenfield regional ISP network, would SRv6 be a requirement? My understanding is that because it's using IPv6 in the dataplane, not all devices have to have SRv6 enabled. The in-between core devices just have to support IPv6, but not necessarily support SRv6. This is much different than traditional MPLS networks today where all devices have to support MPLS/LDP correct?