The amount of experience and cash earned in missions has been reduced in this patch.
At first we though this would be an option or something (based on the wording in the patch notes) that was selectable upon accepting a new contract. However, this seems to be more of a statement about how you choose to play the missions.
Through some testing that a few of us have done we came to the conclusion (while speed running through Hector: Rats on overkill difficulty) that this part of the patch notes is stating that if you choose to skip the mission objectives you will not get anywhere near as much money as you were getting before the patch, but you will still get experience for completing the mission, while if you complete the mission objectives, you will earn relatively more money but still less than before the patch.
Examples of skipping mission objectives include not cooking the meth, burning the intelligence, or not saving as much loot as possible from the bus (in Hector: Rats), not saving the guns in Firestarter, etc