Wayback Machine:

After August 2008 sites had to be listed on the Open Directory in order to be included. According to Jeff Kaplan of the Internet Archive in November 2010, other sites were still being archived, but more recent captures would become visible only after the next major indexing, an infrequent operation.

Please answer a question about this article. If the question is unanswerable, say "unanswerable". When did it become a requirement for websites to appear on Open Directory for inclusion in Kaplan?
unanswerable