Non-developers can expect iOS 8.4.1 to be released in the upcoming weeks with some minor improvements to the aforementioned new features and a bevy of stability tweaks.
iOS 8.4.1 beta 1 sports the moniker '12H304' is able to run on all iOS 8.4 capable devices. However, folks running a Jailbreak on an iOS 8.4 device should know that with every new firmware, there's likely a patch for the latest Jailbreak.
Developers can download iOS 8.4.1 beta from the iOS Developer Portal, or by going into Settings > General > Software Update while running a previous beta firmware.