The main new feature is a new navigation bar visible at the bottom of the index. You now have the ability to browse back to older messages. In preferences you can set how many days worth of messages you want the index to display. The additional index pages will display chunks of messages incremented by the length of time you select in your preferences.
This is handy if you generally check the BBS fairly frequently, but some times don't get back for a while. You can set your preferences to a couple days, but if you don't check in for a week, you don't need to reset your preferences to see what you missed, just use the new navigation bar to click back to read the older messages you had missed.