Automated upgrading with scalafix

http4s-0.22 comes with a scalafix that does some of the migration automatically.

Before you upgrade manually, we recommend you run this scalafix.

Add the scalafix plugin to your project/plugins.sbt or to your global plugins.

addSbtPlugin("ch.epfl.scala" % "sbt-scalafix" % "0.9.28")


$ sbt ";scalafixEnable; scalafix github:http4s/http4s/v0_22"

The compiler errors should help you in showing what’s left to upgrade.

For further information about the changes since 0.21, check the changelog

Help us help you!

If you see recurring patterns that could benefit from a scalafix, please report them for consideration. For general upgrade tips, please consider a pull request to this document.