Talk:Expedition/@comment-82.11.177.163-20140615102000/@comment-24980562-20140615105532

Generally speaking in order to unlock a new expedition you have to complete all other expeditions that come before it. The wiki page specifically points out #26 because it's the longest expedition so far, which means most people tend to avoid it at first because it's not needed to unlock #27 ~ 31 and they don't want to lose a fleet for more than three days when there is farming to be done and there are better expeditions out there. However, when many players finished #30 they started complaining why #35 hadn't been unlocked yet, ignoring the fact that they still had to finish #26.

tl;dr

You need to finish all World 4 expeditions (except #31 because it was implemented later) in order to unlock #35 ~ 39. They mentioned #26 because some people forget to finish it and then start complaining why they can't access World 5 expeditions.