10 July: 24 hours after the El Capitan public beta became available Apple issued a small update that fixed a problem that was causing 32-bit applications to crash.
22 July: The second public beta just appears to include bug fixes.
29 July: Apple released the third public beta of El Capitan at the end of July.
4 August: Apple released the fourth public beta of El Capitan on 4 August. Apple hasn't revealed what is included in this latest beta update.
Bugs in the OS X El Capitan beta
Expect there to be bugs and issues in the beta - the versions of El Capitan available through the Beta Software Program are not finished products, by installing it you are agreeing to become a tester.
For example, in the first public beta there are already issues with 32-bit apps that may quit. "Some 32-bit apps may quit unexpectedly. Affected apps include Scrivener, MacSOUP, Torch, Cisco Jabber, iBiz and others. An OS X Software Update that resolves this issue will be available soon," states the company.
Can I talk about the beta publicly?
There is a license agreement all beta testers must agree to and it specifies that the El Capitan beta is "Apple confidential information." If you accept Apple's terms - and you must in order to partake in the beta program - you agree not to discuss your use of the software with anyone who isn't also in the Beta Software Program.
So you can't "blog, post screen shots, tweet, or publicly post information about the public beta software."
However, you can discuss any information that Apple has publicly disclosed; the company says that information is no longer considered confidential.
How to revert back to Yosemite from El Capitan
Luckily you can always revert to an earlier version of OS X, though depending on how you back up, it's not necessarily a painless process.
Start by making sure the data on your drive is backed up, then erase the drive and install Yosemite. When you first startup Yosemite you can use the OS X Migration Assistant to import your data from the backup.
OS X El Capitan system requirements
If your Mac was able to run Mavericks or Yosemite it will be able to run El Capitan. Those supported Macs include:
iMac (Mid 2007 or newer)
MacBook Air (Late 2008 or newer)
MacBook (Late 2008 Aluminum, or Early 2009 or newer)
Mac mini (Early 2009 or newer)
MacBook Pro (Mid/Late 2007 or newer)
Mac Pro (Early 2008 or newer)
Xserve (Early 2009)
All of those Macs feature a 64-bit CPU. You'll also need GB of space to be available for the install.
Sign up for Computerworld eNewsletters.