It's the way they denote patch numbers. x.x denote major patches, x.x.x denote minor. It's the way a lot of patch naming schemes work & for the last 5 years, it's been their convention.
I would say stop while you're ahead, but you're so far behind it's not possible.
I don't care what they say in the release. I skimmed over the bold titles long before I read the actual paragraphs. It sounds like a major patch to me. New legendary progression, new story progression, new faction, etc.