Whatsapp notification : Puzzled. :S

[AC Question]

I'm messaging a friend who doesn't come online often. So when I last messaged him yesterday at 10.20 pm, there was only a single tick. But when I click on his name now, it's showing double ticks, and a last seen time of midnight. But outside, in the chat list, it still shows only a single tick. Why? :S

Did he block me or something?