Just curious (and I know we haven't been able to remove the Boost dependencies yet) but have you tested with later Boost releases? Also curious why you need this to work with 1.55.

LGTM

I don't see why it wouldn't, but I'll test tomorrow.
As for why I need older boost versions, 1.55 is the default on older Ubuntu, and we'd much rather not package our own shared libs. Our stuff might even need to work on Wheezy and CentOS 6 (gasp!), so I may end up going even lower than 1.55.
This change, however, simply removes a gratuitous version bound, as cpp-netlib doesn't seem to be requiring any newer boost features.

That's fair -- although we do use C++11 features where we can, and I know of older compilers having issues with C++11. If we're going to need to support older compilers, then a pre-C++11 build (0.11.x) would be preferred, though there's a huge delta between then and the current state of the library in 0.13-devel and master.