Slitherine

In the next version of my mod (Italia Victor!) will be buyable ships (core units).

I've alreads implemented to buy ships, but they can't be updated to better models.
I can't find something relevant in the code.
The flag "noupgrade" is not used for the relevant ships.

Is this hard coded and therefore no solution at all

Thanks
Peter

They need to be in the same series.