Soyuz-U retired?

[Danderman]

AFAIK, Soyuz-FG and Soyuz-U are identical except for some engine components, so from the manufacturing perspective, no need for a lot of additional Soyuz-U parts to be ordered to maintain the capability to finish the last two.

I always wondered why Progress did not launch on Soyuz-FG, which has an additional 200 kg payload capability, but I guess the modified engines for Soyuz-FG cost more than the 200 kg of cargo is worth.

Well they did for man rating purposes and it was talked about before Soyuz-2 came into existence.

Since Soyuz-U was already man-rated, the reason for Soyuz-FG was to coax another 200 kg out of Soyuz to accommodate the mass requirements for the Soyuz spacecraft.  The question as to why Progress does not launch on Soyuz-FG probably has to do with drop zones, or the somewhat higher costs of the Soyuz-FG engines compared with the relatively small gain in performance.