a couple of years back, I crossed to the NE USA with blue camping gaz bottles (butane?) and hat to change to propane in the USA because they've never heard of butane - probably because it doesn't work in their colder winters. I also changed the regulator to propane. I didn't do anything to the cooker and it all seemed to work fine.
It was only when I got back to the UK and went back to Gaz that I noticed the kettle took half the time to boil!