Unfortunately, the last game (M2TW) had one turn for 2 years, with summer and winter alternating. A hold over from RTW, obviously.
This game most likely goes back to the turn pattern of RTW.
I think the way some of the moders got around the summer winter default was to have three summers before a winter, which is when character ageing takes place.
If someone plans on moding for four turns, this is what they will need to look at. However, I seriously doubt that this or the next game will have a 4 turn per year sequence.
More likely, they may, if they think it is what the fans really want, try to integrate it into the next engine, when and if work starts on that.
I don’t mean to sound pessimistic but a game with 400 turns is something I think they are more likely to leave to mods.
Bookmarks