Writers can now add bold and italicized text when creating a story in the app, and that is a good improvement over just bare text (though I do wish it offered more formatting options).
The app has also been updated with a new library view, a new pull-to-refresh gesture, and the option to send and receive messages to and from other users. Wattpad is also reporting that this update includes bug fixes as well as improved response time in the library menu.
The update has only been applied to the Android app; I checked iTunes and the iPad app is still on version 3.9.1. It's probably going to get this update in the next week or so.
Changelog for v3.10: