At some point (proposal: in 6 months from now, i.e. November 2017), we should re-evaluate whether it makes more sense to settle for one of the formats. One of our tenets is that familiar formats make it easier for developers to use an API - if we stick with one format for future APIs, then chances are better that developers know it already.
As of now, the section on error handling references both the vnd.error draft and RFC 7807.
At some point (proposal: in 6 months from now, i.e. November 2017), we should re-evaluate whether it makes more sense to settle for one of the formats. One of our tenets is that familiar formats make it easier for developers to use an API - if we stick with one format for future APIs, then chances are better that developers know it already.