Apple has today released iOS 15.1.1. This appears to be an extremely minor update to fix an issue with dropped calls on some iPhone models.
Apple's release notes for iOS 15.1.1 simply say:
iOS 15.1.1 improves call drop performance on iPhone 12 and iPhone 13 models.
As this update appears to have been released to address a specific issue, our expectation is that it does not contain any accessibility changes for blind and low vision users; however, if you notice any changes, improvements or regressions in your own use of iOS 15.1.1, please post a comment below with your findings.
If there is indeed only the above mentioned change in this release, then it may be that it's only available for the effected iPhone 12 and iPhone 13 models. Consequently, don't be surprised if you have another iPhone model and find that iOS 15.1.1 is not offered to you as an available update.
iOS 15.1.1 is available via Over-the-Air Update (Settings > General > Software Update) via Finder on a Mac with macOS Catalina or later, or via iTunes on a PC or Mac with macOS Mojave or earlier.
Before updating, we strongly recommend making a full and complete backup of your device (either locally or in iCloud, depending on personal preference). This will ensure that, in the unlikely event that something goes wrong during the update process, you will have a current backup on hand in case a device restore becomes necessary. Also, if using OTA update, we recommend plugging your device into a power source for the duration of the download/installation process, so as to prevent the unlikely event of your battery going dead during the update.
More information on how to update the software on your device is available on this Apple Support page.