While companies create new microservices-based, born in the cloud, cloud native applications, DevOps and SREs are faced with the challenge of also keeping the lights on for existing apps. In this session we will cover lessons from companies that modernized Windows applications with Kubernetes, what are the most common development and operations pitfalls and how to avoid them, what are the tips and tricks to gain performance, what tools and runtimes to use when adopting Kubernetes and Windows, and how to better run legacy code on Kubernetes. We will also explore open-source projects that companies can rely on and engage as a community. Finally, we will provide demonstrations with real-life scenarios and options for companies getting started into this process.