Originally Posted by Adam Smith

All "direct" flights with stops are affected.

I don't see how LHR-DEL can possibly be harder to upgrade than YYC-LHR. AC sells this as a 5th freedom route, and there are lots of people just buying LHR-DEL-LHR. Being based in the UK where AC has a much more limited presence, those passengers are much less likely to have AC status, meaning less competition for upgrades. And YYC-LHR has usually had very strong paid J demand, meaning limited supply of upgrades. Unless AC is so highly perceived in the LHR or DEL market that there's massive paid J demand, it's likely that the LHR-DEL J cabin is no more full of paid J traffic than the YYC-LHR J cabin. So, similar or greater supply of seats for upgrade, less demand = easier eUps, not harder eUps.