* Janek S. <fremenzone@poczta.onet.pl> [2012-11-09 17:15:26+0100]

> but I am aware that if the library were to be released on Hackage I
> would have to supply version numbers in the dependencies. The question
> is how to determine proper version numbers?

With the current state of affairs, your best bet is not to specify any
version bounds, or specify only lower ones.

Upper version bounds much more often break things that fix things.

I'd like to ask people not to do this. What you're doing then is moving the burden from the maintainer (who has to test with new versions and relax dependencies) to the users of the library (who will be faced with breakages when new incompatible dependencies are released).

Erik