Apple released the first stable build of iOS 26 a couple of weeks ago, ahead of the in-store availability of the new iPhone Air, iPhone 17, iPhone 17 Pro, and iPhone 17 Pro Max.
Now it's back with another update, dubbed iOS 26.0.1. As the name implies, this is a small bug-fixing update that doesn't introduce any new features. According to the changelog, it's meant to fix some issues occurring on the new iPhones.

Here's the entire changelog straight from Apple itself:
The update should already be available to all supported iPhones (and iPads as iPadOS 26.0.1), even though it seems to primarily be intended for the newest models. Since it fixes some important issues, as detailed above, we recommend downloading and installing it as soon as possible.