The N63 issue has been settled, but there are plenty of conditions.
BMW started things called the N63 Customer Loyalty Offer and the N63 Customer Appreciation Program way back in 2014. These came about as a result of N63 twin-turbo V8 engines (the first in the world with a "hot vee" turbocharger setup to be fitted to a production car) that used too much oil.
There were many bulletins and offers surrounding this fiasco, but the end result last we heard was a class-action lawsuit against the automaker. It has grown considerably since then, with the apparent lack of insulation from the hot turbos causing the excessive oil consumption. Whatever the reason, BMW has offered a settlement and it has received preliminary approval.
The lawsuit applies to vehicles with the N63TU engine, including the 2013-2019 650i, the 2013-2105 750i and 750Li, the 2013-2017 550i, the 2014-2016 550i GT, the 20148-2018 X5, and the 2015-2019 X6. There was an earlier lawsuit pertaining to older models with the N63 engine, but this has already been settled. The agreement offers two free quarts of oil for top-offs between oil changes for each future oil change at a dealer. This offer will be available for 10 years or 120,000 miles from the in-service date - whichever comes first - but not less than one year from the effective date of the settlement.
Customers will thus not have to pay for the excessive oil consumption, only remember to top up. These customers are also entitled to up to three free oil consumption tests during the period same as above, should they not have experienced excessive consumption yet.
However, in some cases, the settlement includes "possibly replacing the N63TU engines". As Car Complaints notes, "on the effective date of the engine lawsuit settlement and after one failed oil consumption test, BMW may make one repair attempt or offer the customer an engine replacement. And if a vehicle is repaired and has a second oil consumption test failure, the customer will be offered an engine replacement."
Presumably, replaced engines have been revised to avoid the issue. If the vehicle is still covered by its warranty, the customer will pay nothing for an engine replacement. Of course, many of these vehicles are too old to be covered by their original warranties, and not everyone pays for an extension. If you're unsure of how much you'd have to pay, the below table will help.