[Haskell-beginners] Cabal update possible?

[Obscaenvs]

Have:
* The Glorious Glasgow Haskell Compilation System, version 7.6.3
* cabal-install version 1.16.0.2
  using version 1.16.0 of the Cabal library

Can I update to Cabal 1.18 so I can use sandboxes without breaking my
dependencies? I think that that is what broke my Haskell toolchain 2h
ago. Now I redid it so everything's fine, but I'd like to use sandboxes.
If impossible, hsenv has worked for me in the past, but...

I did not want to use Haskell Platform, since it pulls in several OpenGL
libs completely unnecessary *for* and potentially detrimental *to* my
server. "Haskell Platform, Server Edition", anyone?

fredrik