Hi all, I have released 1.22.8.0, 1.20.2.0 and 1.18.2.0 of cabal-install, after a fix was found for #3003 https://github.com/haskell/cabal/issues/3003: If you encounter an error similar to the following when running `cabal install cabal-install` or 'cabal install Cabal': /tmp/cabal-tmp-7012/Cabal-1.22.6.0/Distribution/Version.hs:135:10: Duplicate instance declarations: instance Binary Version -- Defined at /tmp/cabal-tmp-7012/Cabal-1.22.6.0/Distribution/Version.hs:135:10 instance [safe] Binary Version -- Defined in ‘binary-0.8.0.0:Data.Binary.Class’ try running 'cabal install -j1 Cabal' to work around the 'binary-0.8' compatibility issue. Cheers, ryan