If you decided to play Cold War Crisis, Red Hammer or any of the available player-made campaigns under OFP: Resistance and then revert to playing them under an older OFP version, you'll get an error message and you won't be able to play them. The error message will be similar to the following example (showing an attempt to play the 1985 Cold War Crisis campaign): 'Users\player_name\Saved\Tmp\1985.sqc.raP': '|' encountered instead of '='.
This is because OFP: Resistance saves campaign information in campaign SQC files in a different format than in older OFP versions, which do not recognize the new format.
There are three ways to resolve this problem: