Hi everyone, servant-0.20.1 has a release candidate available! It is a compatibility release to support aeson-2.2. You can test it easily by modifying your cabal.project file like this: packages: ./ https://hackage.haskell.org/package/servant-0.20.1/candidate/servant-0.20.1.tar.gz and adjusting the version in your freeze file. Please report problems here: Allow aeson-2.2 by maksbotan · Pull Request #1695 · haskell-servant/servant · GitHub