Developers got their talented hands on the betas of OS X El Capitan, iOS 9, and watchOS 2 a couple weeks back at WWDC. On Tuesday, Apple released second version of all three of those developer betas.
To get developer betas, you need to be part of Apple's Developer Program, which is now just one program--formerly, devs had to register separately for OS X and iOS.
Developers who already have the first beta of iOS 9 installed can upgrade over the air, or download it from Apple's Developer Resources. The OS X El Capitan beta is available in the Mac App Store, on machines already running the first beta, or from the Mac Developer Center.
The second beta of watchOS 2 comes to developers through the Apple Watch app found in today's updated iOS 9 beta. Developers also need to install a watchOS 2 configuration profile found on Apple's website.
Developers also have access to a beta of iOS 8.4, which should launch for regular consumers next week, bringing the all-new Music app and Apple Music streaming service. Apple Music is scheduled to launch on June 30. iOS 8.4 hasn't gone to Gold Master status yet, but it's just a matter of time.
The impact on you: These are public betas, but those follow along a few versions behind the betas developers get. Apple has announced that it will have a public beta program for OS X 10.11 El Capitan as well as iOS 9, beginning in July--that's just around the corner. Public betas are a fun way to get access to new features before the final versions of El Cap and iOS 9 ship to the world, but they also require a lot of updating, and could introduce snags into your workflow. Apple recommends developers install the betas on test devices, not their everyday machines they rely on to actually get stuff done--but not every "regular" user has an extra Mac, iPhone, or iPad lying around. (At least with a Mac, you could install the beta on a partition.)