The 2006 competition's challenge was to demonstrate that a team of robots could pass the ball. More recent challenges have focussed on robot-robot cooperation without WiFi connection and playing soccer on uneven terrain (i.e., artificial grass instead of a carpet).
In the context of robotics competitions, the 2006 challenge was to demonstrate that a team of robots could successfully pass the ball. Subsequent challenges have focused on robot-robot collaboration in situations where WiFi connectivity is not available and robots must play soccer on an uneven surface, such as artificial grass.