A complete rebuild of the TSR app - it's based on Tapatalk, which limits what can be done with it. I, like others, would like to see a 'who quoted me' section, and the ability to give rep.
From a modding point of view, the interface that is used to move threads on the app is very nice. In contrast, the browser version forces you to select from an extremely long drop-down list, and so it can be very cumbersome to find the forum you want.