watchOS 4.3.1

On Saturday, Sept. 1, Apple will celebrate the 50th anniversary of Redwood National Park. In doing so, you’ll receive an Apple Watch Activity Challenge reward when you do a walk, run, or wheelchair workout of 50 minutes or more on that day using your wearable device.

First discovered by Kyle Seth Gray and posted on Twitter, the latest Apple Watch Activity Challenge is the first for U.S. users since Earth Day was celebrated in April. The last challenge worldwide occurred last month when Chinese Apple Watch users celebrated National Fitness Month.

Like previous Activity Challenges that promote exercise and wellness, the one commemorating Redwood National Park’s 50th anniversary will unlock an animated themed sticker in the Activity app for Messages. It also includes an award in the iPhone’s Activity app.

In iOS 12, Apple is substantially increasing the number of animated Activity stickers available in Messages. These don’t require completing an activity challenge. Instead, they each represent a type of exercise, such as running, swimming, and walking.

Cupertino’s expected to reveal a fourth-generation Apple Watch in the coming weeks alongside new iOS devices for 2018. This year’s wearable device is likely to feature smaller bezels and a larger screen than the previous design.

Do you use the Apple Watch Activity Challenges? Let us know below.