Simplify the following text for a Grade 11 native English-speaking person.
Original: In 2005 the contract was amended to permit the system to be extended and modified as work on the replacement myki project progresses , with the contract being able to be terminated on six months notice .
Simplified: In 2005 the contract was changed to permit the system to be extended and changed as work on the replacement myki project keeps going , with the contract being able to be canceled on six months notice .