This summer, Apple let every OS X user with a qualifying machine who wanted to opt into a public beta do so with a very few clicks. In fact, you still can: Visit the Apple Beta Software Program enrollment page, download an installer, and follow the instructions.
El Capitan’s public betas were very stable, even in early releases, and Apple’s incremental approach coupled with extensive testing truly seemed to help produce a mature “dot oh”: OS X 10.11.0 worked well out of the gate. But what if you don’t want to preview all the micro-releases, like the curent 10.11.1? As long as you’re in the program, you’ll get daily reminders about these new betas.
Read more here:: How to leave the OS X beta program