The cosmic censorship conjectures concern the singularities arising in general relativity. In May the QuantaMagazine published an article (link) about a potential disproof of a strong version of the cosmic censorship conjecture. This article is nicely written and I recommend everybody interested in general relativity reading it.
The preprint the QuantaMagazine refers to is arXiv:1710.01722 and was posted in October 2017. It is not yet published, hence one should probably treat it with some care (not claiming that being published makes articles automatically correct), but a reason for this might be that it is 217 pages long! That surely takes some time to review.