During the recent improvements the fields for next/previous post number were removed. This normally would have been fine except every once in a while danbooru glitches and doesn't fill in the next post number (like with post #137074). Previously I was filling in these numbers as I browsed, but alas.
I'd rather not report every time I run into a snag but if we don't want to reimplement the boxes I can, in this thread.
Updated by LaC