1. You’re using the latest version actually. It is because there is no data to show, it require traffic to some posts so the popular posts plugin can fetch data. Do you have traffic already? You can also view several of your posts for manual generated data.
2. The popular posts show monthly top views posts. As I mentioned at point 1, it require traffic to fetch data.
If you use any caching plugin such as WP Super Cache or W3 Total Cache, please try to clear cache.