You can still upgrade most domestic flights using miles, but if you're planning to upgrade to BF, you have to buy an H or Y fare to avoid the fee. And if you're flying to Hawaii, you have to buy a Y fare. Otherwise, it's at least $400 round trip, and up to $800 on the lowest fares.

It's not clear on partner upgrades, but my own interpretation says that there isn't a fee.

Still, this strikes me as an extremely unfair international upgrade policy.