This is probably worth sharing since I know many probably many people here use the united miles as I do.
I found out that United will be adding four new upgrade-eligible fare classes for flights operated by Turkish Airlines.
This means that you can use the M, A, H, and S fares discounted coach tickets for a more affordable Turkish Airlines ticket.
So for example, if you have a round-trip ticket from New York to Istanbul, a B-class fare would run you about $2,325.
An S-class ticket on the same flights is going for $1,485 which is going to be significantly more affordable than one in B class.So in addition to the $1,485 ticket, you’ll need to shell out 25,000 United miles in each direction to upgrade to business class.
This could actually represent a good deal, depending on how much the underlying S-class coach ticket costs.

If you were to outright redeem United miles for a Turkish business class seat on this route, you’d need to shell out 154,000 miles round-trip.
By redeeming an upgrade instead, you’d be out 50,000 miles and $1,485 for the coach ticket (and you’d still be eligible to earn miles on the ticket).