In previous versions, you had to configure email connection details per [Email Stage](../../flow/stages/email/index.mdx). Now, you can (and should) configure global settings.
Download the docker-compose file for 2021.1 from [here](https://goauthentik.io/version/2021.1/docker-compose.yml). Afterwards, simply run `docker-compose up -d` and then the standard upgrade command of `docker-compose run --rm server migrate`.