What is happening is that all of the stuff that I have been explaining in the "Local fix" section for a decade and a half, alongside the practice that clients had of timing out and then retrying the transaction without the extensions, is now being declared moot. If DNS lookup does not work because of this problem, it is being declared entirely the server-end's problem. Clients are no longer going to be expected to put such local fixes in place, or have timeout and retry bodges.
As someone who's been required to maintain bug-compatible software before, this fills me with great joy. Congratulations on getting to deprecate the brokenness!
What is happening is that all of the stuff that I have been explaining in the "Local fix" section for a decade and a half, alongside the practice that clients had of timing out and then retrying the transaction without the extensions, is now being declared moot. If DNS lookup does not work because of this problem, it is being declared entirely the server-end's problem. Clients are no longer going to be expected to put such local fixes in place, or have timeout and retry bodges.