Sony has opened its PlayStation 4 software beta program to anyone, letting users sign up to test early versions of new system firmware before they're released to the general public. You can sign up to participate here as long as you have a PS4, though Sony warns that space on the program will be limited.
Beta testers will get the first version of what Sony calls its "next major system software update" from early September, and if anything goes wrong they should be able to downgrade to the stable v2.57. Sony hasn't yet said exactly what the update will contain.
Microsoft operates a similar beta-testing system called the Xbox Preview program for both the Xbox One and the Xbox 360.