Is univalue compatible with json?
I have been trying to use a miner for solo on the new version of bitcoin with no success.
Univalue should be _strictly_ compatible: strictly producing and strictly enforcing.
Many things that produce JSON produce incorrect encodings, and many things that consume JSON will accept incorrect encodings. That may be the case here, or there could be a bug in univalue. Without seeing your software, its hard to say.