Based on what I know on Android apps is there could be the same version released but different based on the device you're using. My advice is to wipe the application clean and restore its defaults. To do this, hold your finger on the Flud icon and then drag it to the App info button. Once there, tap on Clear Cache and Clear Data. Open the app again and configure it (as necessary), then check the search engine selection. If it's still not possible, consult the updates page on Play Store and make sure they're actually the same, otherwise report this issue to the developers.
