You can download the update by heading to Settings > General > Software Update on your iPhone or iPad.

In the release notes, Apple mentions unspecified bug fixes and other improvements.

At the same time, Apple also released watchOS 8.7.1 with bug fixes and other improvements.

watchOS 8.7 can be downloaded now through the companion Watch app on your iPhone by heading to General > Software Update in the My Watch portion of the app. You can also go to Settings > General > Software Update on an Apple Watch

Your watch needs to have more than 50 percent power and connected to a charger. Like most Apple Watch updates, it could take anywhere from 30 minutes to an hour to complete, so be patient.

It’s compatible with the Apple Watch Series 3 and later.