There are 5 updates planned up to October 2021.
Capcom has revealed a new trailer detailing its planned update schedule for Monster Hunter Stories 2. These updates will be adding new Monsties as well as new Quests.

As can be seen in the above image the schedule is as follows:
- July 15 – Palamute as a new Monstie
- August 5 – Hellblade Glavenus and Boltreaver Astalos as new Monsties, and Kulve Taroth as a Co-op quest exclusive monster
- Early September – Soulseer Mizutsune, Elderfrost Gammoth, and Oroshi Kirin as new Monsties
- Late September – Dreadking Rathalos and Molten Tigrex as new Monsties, and a high-difficulty Kulve Taroth as a Co-op quest exclusive monster
- October – Silver Rathalos and Gold Rathian as new Monsties, and an unknown high-difficulty Co-op quest exclusive monster
You can check the trailer out here:
Monster Hunter Stories 2: Wings of Ruin launches on the 9th of July 2021 (that’s next week)!
Source: RPG Site