No one has that answer, even Codemasters/EA aren’t 100% certain yet.
I think 2024 could be an update, I don’t think there’s massive changes in WRC, aside from the additions of Latvia and Poland to the calendar, replacing Estonia and Mexico, there isn’t much else. So the cost of development vs cost of a season update vs new game is potentially much tighter.
2025 however could see bigger changes, with a technical refresh to Rally1 regulations, new tyre supplier, and rumours of USA, Saudi Arabia and Ireland as host rallies not going away. As this would naturally take a lot more work than the 2024 season, I could see this being a full release rather than an update as there would potentially need to be revised tyre physics, 3 huge new rallies which are all vastly different plus a technical overhaul in Rally1, which is , firstly, a huge amount of work to undertake, but also, not cheap and needs a full priced end product to make it worthwhile.