The historical lock notices emphasizes:
it is not considered a good, on-topic question for this site
That said, we could try and keep up the post, but then we'd be diverting energy away from maintaining other aspects of the site that are good fits for the site.
To that end, please don't flag moderators or post to meta to to have it unlocked so you can perform edits/changes, it's simply not worth everyone's time.
It's also my opinion that over time, historical locks should lead to deletions, as the usefulness of the content on the page will eventually rot away (quality/content-wise) and the primary condition for the lock (that the content be of value) will no longer be applicable.
Your request is an example of that; the link is broken, and we have a broken window on the site.
I'd personally be more inclined to delete the answer, as editing it makes no sense; Stack Exchange is not the place to archive this content. Your blog or other medium is a better choice if you're worried about the content being preserved beyond its usefulness.