docs: refine message about aks-engine project status

README.md

@@ -5,11 +5,13 @@
 [![GoDoc](https://godoc.org/github.com/Azure/aks-engine?status.svg)](https://godoc.org/github.com/Azure/aks-engine)
 [![Go Report Card](https://goreportcard.com/badge/github.com/Azure/aks-engine)](https://goreportcard.com/report/github.com/Azure/aks-engine)
 
-AKS Engine is a legacy ARM template-driven way to provision a self-managed Kubernetes cluster on Azure.
+## Project status
+
+This project is stable, meaning the pace of new features is intentionally low. AKS Engine is maintained by teams who depend on it including [AKS Engine on Azure Stack Hub](https://docs.microsoft.com/en-us/azure-stack/user/azure-stack-kubernetes-aks-engine-overview).
 
 ## Overview
 
-AKS Engine provides tooling to quickly bootstrap Kubernetes clusters on Azure. By leveraging [ARM (Azure Resource Manager)][ARM], AKS Engine helps you create, destroy and maintain clusters provisioned with basic IaaS resources in Azure. AKS Engine is limited in its support for ongoing operational needs such as scaling, in-place upgrading, and extension management. The [Cluster API Provider for Azure a.k.a. CAPZ](https://capz.sigs.k8s.io/) provides more complete operational capabilities. AKS Engine remains the tool for managing Kubernetes clusters on Azure Stack Hub as CAPZ does not yet work there.
+AKS Engine is an ARM template-driven way to provision a self-managed Kubernetes cluster on Azure. By leveraging [ARM (Azure Resource Manager)][ARM], AKS Engine helps you create, destroy and maintain clusters provisioned with basic IaaS resources in Azure. AKS Engine has limited support for ongoing operational capabilities such as scaling, in-place upgrade, and extensions. The [Cluster API Provider for Azure a.k.a. CAPZ](https://capz.sigs.k8s.io/) provides more complete operational capabilities. AKS Engine remains the tool for managing Kubernetes clusters on Azure Stack Hub as CAPZ does not yet work there.
 
 ## Getting started