If you see this sign at the end of an episode, it means that this is currently our last level available at the moment but new contents will arrive soon.
Please remember that our team works on creating new levels as soon as possible. It’s not an easy task, when you take into consideration that we already have several levels in the game and the team need to create new, fun and challenging layouts which are not repetitive or too similar to previous levels - but also perform correctly, are achievable and make use of new Boosters and other features. The work is constant.
Try updating your game to it's latest version. If your game is already up to date, it means that the new levels are currently in the making and will be there soon for you to enjoy!