For the last few months we've been collecting stats about download habits. The results are that most members stick to one format. For ebooks it's either EPUB all the time, or Kindle all the time. For document files, it's either html/zip all the time or .txt all the time.
So in order to simplify the site's interface and be more efficient, we've made a slight change.
As of today, the default download buttons are Zip and EPUB.
Don't panic! You can get what you prefer through the download preferences page:
https://storiesonline.net/sol-secure/user/downloads.php
You can choose to have all the buttons show up like before or pick the format that you want for those two buttons.
Also, the option for the default document download format controls the chapter download button in serials' index pages. If you choose Zip, then clicking the download icon for a chapter will download the html version like before. But if you have .txt, then that link will download a .txt file for you.