No, you should read the article. They cite the previous review by seven intelligence agencies. That had been publicly reported, so for folks who had been following it, the consensus was most recently that it wasn't a mystery weapon.
Another part of this is that these agencies by temperament hedge their answers and were remarkably unequivocal, noting "new evidence could change their mind" -and they have become less unequivocal. This strongly suggests new evidence, but since this is in the secrecy-strategic space, we're not going to know.
It could be somebody senior said "change tone of voice" or it could be something new was found. We can't know.
