The 2.2.1 beta can be downloaded through the dedicated Apple Watch app on an iPhone by going to General --> Software update. To install the update, the Apple Watch must have 50 percent battery, it must be placed on the Apple Watch charger, and it must be in range of the iPhone.
It's not yet clear what is included in watchOS 2.2.1, but Apple's release notes say it includes bug fixes and performance improvements, likely for issues discovered since the release of watchOS 2.2. We'll update this post with any new changes that are discovered in the watchOS 2.2.1 beta.
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