Originally Posted by burlax

You won't be upgraded from X/I/O fare class. This simply will not happen.

Upgradeable fare classes are listed in the M&M T&C.

Also, LH doesn't open upgrade availability until very close to depature, so using other airline miles is problematic since you cannot get on the upgrade waitlist.

Also, you'd need a Y/B/C/D fare class to use other carriers' miles. If you want to upgrade a discount fare, you'll need to use M&M miles.