[0.13]mod migration - "No covariant prototype to load"

[Tardan]

I tried to migrate one of my mods 0.12 to 0.13. But I have a problem. The following error message appears when loading a saved game 0.12:
"No covariant prototype to load medium-basic-transportation-belt-to-ground, did what saved as type transport-belt-to-ground, but is now underground-belt"

what I did: I changed the type of an entity from
     type = "transport-belt-to-ground"
to
     type = "underground-belt"

because there the type transport-belt-to-ground was changed. This creates I think the error message. What can i do now?

[Ranakastrasz]

Having the same issue, albiet with a different entity type.

[orzelek]

It's a bit of a hunch - try to rename your entity and then apply a migration that renames old one to new one - this is what seems to be done in base game. Might work on modded underground transport belts also?

[scherzeking]

Did you got a solution yet?

[canicon2]

Gives any solution for this problem?

i have the same:
(No covariant prototype to load express-transport-belt-to-ground-extended, that was saved as type transport-belt-to-ground, but is now underground-belt)

i changed all types to underground-belt but have everytime an issue