https://wccftech.com/apple-releases-ios-13-5-gm-with-exposure-notification-api-and-faster-face-id-unlock/

Apple has released iOS 13.5 and iPadOS 13.5 GM builds to developers, with exposure notification API, faster Face ID unlock, tweaks to FaceTime video tiles, emergency services update and more. The update is now available for iPhone, iPad and iPod touch as over-the-air update, as well as from Apple Developer Center.

iOS 13.5 had initially released as iOS 13.4.5 beta, but when Exposure Notifications API was announced, an SDK update was required, which meant that the version number also had to be updated.