Apple has today released iOS 9.3.4 to the public, bringing an 'Important Security Update' to iOS 9 users.
According to Apple's release notes via Mac Rumors, iOS 9.3.4 contains "an important security update" and is recommended for all those using iOS 9.
As iOS 9.3.4 appears only to be a security-fix update, it is unlikely that there are any accessibility changes for blind and low vision users. However, if you do notice any changes, please do let us know in the comments.
iOS 9.3.4 is available via Over-the-Air Update (Settings> General> Software Update) or via download in iTunes. As with any software release, we recommend that you back up your device before updating to iOS 9.3.4.