There are 2 tables on the page. The first is until December 31, 2023; the second says it takes effect January 1, 2024.
The quoted text that snorkmaster is refering to doesn't come from the chart. It's from the "What to know about upgrade priority" section after the chart.
The sentence about fare classes isn't flagged as being obsolete in 2024, though other bullet points in that list are specifically mentioned as being so.