I have been using YARRP since 2009 and it was working fine back then.
But in 2011, I changed design of website and so removed this because I no longer need to show related posts on website.
Last month, I changed design again and from last few weeks I am using YARRP again. But I noticed yesterday that YARRP is not working for old posts prior to 2011 (when I deactivated plugin) but showing related posts in new posts after 2011.
What is wrong?