At least. I remember finding his site back in 2004 and it felt long in the tooth then. Complete with blink tags.
He brought it up in 2001, the year XP was released[1]. Microsoft fixed it three years later in SP2. XP was EOL'ed in 2009[2].
[1] https://en.wikipedia.org/wiki/Steve_Gibson_(computer_program...
Do keep in mind, however, that his entire reason for continuing to publicize this was because it allowed him to continue making foolish claims like "Microsoft Does Not Understand Security," and to pretend that the eventual restrictions (not removal) of raw sockets in XP were proof that he was right. They were not.
In fact, the entire issue was over his own misunderstanding of security. You can't secure a network by asking client operating systems to restrict their own behavior on some kind of honor system (guess what: the bad guys' computers will not have these restrictions). The use of raw sockets did not disappear and the internet still exists. The claim that this was "a tremendous threat to the global Internet" basically amounted to "the sky is falling and only I can see it because none of the other security experts 'get it' like I do." Which is entirely bogus.
Has he done anything of note since? I mean, other than the extremely timely spinrite podcast? Honest question; I browsed through the website and it still seems to be mostly filled with questionable security alarmism from the 200x era.
Shields Up is timeless, but doesn't do IPv6 and probably never will. There are some smaller apps that were done recently, less notably. Security Now podcast is ongoing.