The main change between any other year was a co-ordinate based movement system. Any input taken in from the camera was converted to co-ordinates, so we could plot our movement more accurately and allow for any immovable objects such as the internal walls.
The addition of this coordinate system allowed us to create the killer feature of this year, the position correction code. This code allowed us to automatically correct our position after we scanned for a marker, so we could allow for the motors not moving us exact distances.
Unfortunately, due to the number of features, we have decided to keep the source internal. A lot of blood, sweat and tears (not literally) went into writing this code, and it would be a shame if that were to be used to help any of our opponents.