Currently, xmonad does not build against the packages in the latest Stackage LTS release, in particular utf8-string-1. It would be great if xmonad would join stackage so that such problems are detected early. It also gives you some QA for free: http://www.stackage.org/authors

I just tried bumping the upper bound on the utf8-string dependency to ">= 0.3 && < 1.1" in xmonad.cabal and it appears to build fine against Stackage LTS 2.7. So I believe this is a one-line fix. A grep of the xmonad source reveals no use of the deprecated imports that were removed in the bump from 0.3.x to 1.0, and the same holds for XMonadContrib. I'll submit a patch.

Awesome, thanks!

Can you also send a pull request to add it to Stackage? http://www.stackage.org/authors

Created https://github.com/fpco/stackage/pull/584

The pull request has been rejected because my patch to increase the bound on utf8-string hasn't made it to a released Hackage version yet. Is there a release planned yet? Does this merit a full point release on its own?

With my Debian packaging maintainer hat on: Yes, it does merit a release, either on its own or a proper new release.

Any plans for a point release with this patch?

Bump. Still waiting on that release.