A couple of days ago Rancher have released Rancher version 2.1.1 as latest and stable: https://rancher.com/docs/rancher/v2.x/en/
Rancher v2.1 introduced new improvements to Kubernetes cluster operations and app management, as well as a migration path for users moving from Rancher's Cattle orchestrator introduced in 1.x to Rancher Kubernetes.
You can also use Rancher 2.x to create clusters in a hosted Kubernetes provider, such as Google GKE.
The following Kubernetes providers are supported in Rancher 2.1:
Rancher 1.6 to 2.1 Migration documentation:
https://rancher.com/docs/rancher/v2.x/en/v1.6-migration/
Rancher 2.1.1 Release Notes:
https://github.com/rancher/rancher/releases