"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
Apple Seeds Fifth Beta of iOS 10.3.2 to Developers
Registered developers can download the fifth iOS 10.3.2 beta from the Apple Developer Center or over-the-air with the proper configuration profile installed.
Apple doesn't provide detailed release notes for its beta updates, so we don't yet know what features, improvements, or bug fixes might be coming in iOS 10.3.2, aside from some fixes for SiriKit car commands that were outlined in the release notes for the first beta.
As a minor 10.x.x update, we can expect iOS 10.3.2 to offer bug fixes and performance improvements rather than outward-facing features. No notable changes were found in the first four betas, but if anything new is found in the fifth iOS 10.3.2 beta, we'll update this post.
Update: iOS 10.3.2 beta 5 has also been released for public beta testers.