Release notes are up on GitHub
v3.7.0-alpha.1 and the new images have been pushed.
Of major note - in 3.7 OpenShift RBAC will shift to being a layer on top of Kubernetes RBAC (preserving your existing roles). Existing APIs will continue to be supported, but unlike 3.6 where Kubernetes RBAC was automatically kept in sync with OpenShift RBAC, starting with 3.7 the canonical source of authorization will be via the Kubernetes RBAC APIs.