Monster Hunter Stories 2 has been updated to version 1.5.0 today by Capcom. You can find out the complete patch notes for this update from here.
Capcom is continuing to churn out new content in the game with these updates. The latest patch appears to add new monsters like Fatalis, Silver Rathalos, and Gold Rathian. They will be available as part of the in-game quests and co-op events. You can get the details on this update below, or have a look at them on the official website.