As a package maintainer you might be observing an increasing number of questions raised by people that have recently migrated to R 4.0.0 and are now trying to get your package to work. While migrating to a new version is always tempting maybe you don’t feel like disrupting your development environment just now as you have even more fun things to do. Fear not! A quick docker container can help you to test your package and its functionality without touching your main environment. Let me show you how.