It will last for 10 weeks. Based on this you will only have to do roughly 60-65% of the objectives/missions. Source: Rebecca’s Twitter post (https://twitter.com/rebbford/status/1100864824433610753?s=21) On a unrelated note, the zenistar is still bugged. You have to attack a few times and then charge attack to throw the disc. The “just” charge attack doesn’t release the disc currently.