The situation is slightly confusing: The change to IDFA handling was meant to roll out as part of the iOS 14 update. However, the change was delayed, but the rest of iOS 14 was not.

As my fellow responder indicted, iOS14 was indeed released in September and I came here to comment on this extremely odd and incorrect statement myself. As the OP states, Apple merely postponed the IDFA functionality.

I cannot prove it, but this whole piece reeks of being algorithmically generated, and I do believe that this factual error is proof of that. Any human journalist operating in the field of technology would be well aware that iOS14 has already been released and would have phrased accordingly; I think that what we’re seeing here is some algorithmic synthesis of background facts (one of which was apparently source of confusion, because of references to iOS14 and postponement, not of the whole OS but of a relevant portion thereof).

Indeed! The article doesn't even link to Apple's statement, which makes me feel as though the writer is cherry-picking here.

The IDFA opt in requirement was not added to stable release of iOS14