Originally Posted by
RedChili
As Fransknorge wrote, upgrades on Turkish are only available in classes Y and B. A quick search for random dates in February shows CDG-SGN-CDG available in B at EUR 2,840. The upgrade itself would cost 100,000 miles, and you would earn around 13,000 miles for the ticket. In addition, an upgrade would also trigger a recalculation of taxes and surcharges. Itamatrix indicates an increase of 334 in taxes, thus putting the total cost at 3,174 euros plus 87,000 miles.
Thanks for doing the job for me

So it would actually be much more expensive