Apple seeded the fourth beta of an upcoming watchOS 4.2.2 update to developers, one week after seeding the third beta and more than a month after releasing watchOS 4.2, an update that introduced support for Apple Pay Cash. 

Once the proper configuration profile has been installed from the Apple Developer Center, the new watchOS beta can be downloaded through the dedicated Apple Watch app on the iPhone by going to General --> Software update. 

To install the update, the Apple Watch needs to have at least 50 percent battery, it must be placed on the charger, and it has to be in range of the iPhone. 

We don't yet know what features or improvements might be included in the watchOS 4.2.2 update, as no outward-facing changes were discovered in the first three betas.