You definitely want to upgrade to the 1.1 firmware, which was released shortly after the wifi unit came out. Here's a link to the MTH 1.1 Upgrade Page
You should also update your TIU and Remote to the 6.1 version of DCS. There have been some needed fixes in both these updates. The TIU and Remote firmware should always be the same version. DCS version 6.1 also has some fixes you probably need.