Just checked

1. Click: https://nc-client.jarunik.com/activity
2. Filter > Upgrade Yamato
   

Funny to see people trying to upgrade something that is not there yet :)

I still need to read a lot about Yamato ... got the skills at 20 but still no idea how to get one except finding one of these almost not findable planets.
Yes, you already wrote a lot about it - that's why I need to read more :)