At WWDC 2015 Apple announced that it was letting the public test the upcoming new version of the Mac operating system - OS X El Capitain - as part of its new, free beta program.  Apple's OS X Beta Seed Program is now live, so here's how to sign up to download the beta version of the software.

The program will let you download and run beta versions of OS X 10.11, there will be multiple versions as Apple irons out the bugs and glitches. Those who register for the OS X Beta Seed Program can download the software, and begin giving feedback to Apple to help the company perfect the update before it's released to the public in the autumn.

To sign up to the program now just visit Apple's website here. If you have previously signed up just visit that page and log in to receive your download code, more on that below.

In 2014 there was an email included a redemption code for downloading the beta, this year it appears there is no email, you just need to log on tp Apple's website with your Apple ID.

Last year's programme was the first time Apple has ever opened a Beta Seed Program. The company did release a Public Beta of OS X in 2000, but those who wanted to download it had to pay $30 for the privilege.

Registered Apple Developers are able to download pre-release versions of most of Apple's software too, but it costs $99 per year to register as a developer.

You can read all about the new version of OS X here plus, Here are our top ten features coming in OS X El Capitan and How El Capitan compares to Yosemite

Also: Find out how to download and prepare for OS X El Capitan.

If you install El Capitan and then think you made a mistake, here's How to remove El Capitan and revert to Yosemite

The risks of Apple's OS X Beta Seed Program

It's worth noting that participating in Apple's OS X Beta Seed Program is not a light undertaking, so you should consider whether it's really right for you before downloading and installing the pre-release software. After all, being pre-release software, it's bound to have bugs and issues that could cause things to go spectacularly wrong with your Mac, which isn't helped by the fact that Apple is not obligated to provide any support for pre-release software.

If you only have one Mac, and you're intending to run the pre-release software on that machine, you might want to reconsider. Apple suggests that you should run the pre-release software on a dedicated Mac, not a Mac that you use for business or production purposes.

There's also the important matter of privacy. By agreeing to test the OS X beta software, you're essentially giving Apple permission to collect diagnostic, technical and usage data from you, unless you go through the process of opting out.

Last year the first beta version of OS X 10.10 Yosemite came with several known issues, including problems in Safari while trying to access Netflix content, iPhoto, Photo Stream and iCloud Photo Sharing problems, iCloud Drive issues and AirDrop issues, so beware.

See also: Safely install the Mac OS X beta by dual-booting and How to partiton your Mac

If you're still interested in signing up to the OS X Beta Seed Program, here's what you'll need to do.

If you install El Capitan and then think you made a mistake, here's How to remove El Capitan and revert to Yosemite

How to sign up to the OS X El Capitan Beta Seed Program

First, you'll need to go to the OS X Beta Seed Program website. From there, you can find out more about the program by clicking Learn More or FAQ.

You must be aged 18 or older with a valid Apple ID, and you'll also need to be willing to accept the Confidentiality Agreement, which means you agree not to share information or screenshots of the update.

By clicking 'Join Now' and then 'Get Started' on the OS X Beta Seed Program website, you'll be taken to the 'Sign In' page. If you don't already have an Apple ID, you can create one by clicking 'create one now' in the grey box on the left. If you do have one, however, you can go ahead and sign in using the password you normally use for your iTunes and other Apple services.

Next, you'll be taken to the OS X Beta Seed and Confidentiality Agreement. You'll need to read the agreement (you can view it as a PDF if you prefer by clicking the link beneath the scroll link) and then click accept. Unless of course you don't agree with the terms in which case you'll want to stop the registration process now.

Also: Will your Mac run the new OS X? Check the requirements here.

Once you are registered for the Apple Beta Software Program you will need to enroll your Mac here in order to be able to get the updates from the Mac App Store. You will have to re-enroll your Mac if you had previously been a tester for Yosemite.

You will find a download link and you redemption code on that page. Click on the link and enter your code to download El Capitan.

But hang on, there are a few things you should do first, not least be absolutely sure that you want to run the beta...

How to get your Mac ready for El Capitan beta updates

Apple gives clear instructions about how to prepare for the install on the Enroll your Mac page.

First Apple advises users to make a backup of their data and files before installing any beta versions of OS X, stating: "Always back up your data and files before installing beta versions of OS X. If you have multiple Macs, we recommend installing OS X El Capitan Beta on your secondary computer. Backing up files on a Mac is easy with Time Machine, the built-in backup utility in OS X."  You can find out how to use Time Machine to back up your Mac here.

You'll need to have OS X Yosemite installed and have 2GB or more of memory with 8GB or more of available space.

Once installed the app will launch the Mac App Store, which will show you if any updates are available (currently there is a pubic beta for OS X Yosemite 10.10.4). Any updates that have not yet been released to the public and are therefore part of the OS X Beta Seed Program will be labelled 'Pre-release'.

You can click update to install those pre-release versions of software. Just need to click Update to install the most current version of the OS X Public Beta.

With each new release, the latest OS X Public Beta will automatically appear in the Mac App Store and you’ll receive a Notification when it is available.

What does being a beta tester involve?

The purpose of the beta program is to provide Apple with feedback about the upcoming OS. If you experience bugs or other issues, report them to Apple using the Feedback Assistant app. And don’t just say something crashed, explain exactly what you were doing when the crash happened and try and reproduce the crash to see if you can identify what steps lead to it.

Don’t just tell Apple that you don’t like the ‘flat’ look of the user interface. Your purpose as a beta tester is to provide feedback on bugs, not try and assume Jony Ive’s role.

That said, it won’t always be bugs you need to provide feedback on. Perhaps you can’t work out how to do something and a user interface tweak is required.

You can also provide feedback if third party apps aren’t working as they should - there is actually a 3rd-party Application Compatibility category in which to submit feedback.

Bugs in the 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.

How to send feedback to Apple

You'll find the Feedback Assistant in your Dock (it's a purple circle with a speech bubble within it, as shown above). Click it and then sign in with your Apple ID to begin providing feedback to Apple using the form that the Feedback Assistant provides.

Launch the Feedback Assistant app. Start with the Questions screen > select the topic about which you’re providing feedback > describe the issue in a sentence >  then provide a detailed description, including any steps that reproduce the issue if you have been able to identify them.

Now that you've signed up to the OS X Beta Seed Program and have installed the OS X beta, you'll be able to provide feedback to Apple about bugs and other issues that need to be fixed.

Public vs developer preview - what's the difference?

The public beta is not the same as the beta being released though the developer program. it is likely that developers will receive more frequent updates including new features not in the public beta.  

What’s in the 1st public beta of El Capitan?

The first public beta is the same as Developer Beta 3, also released this week. That means it at least has fewer bugs and is slightly more stable than Developer Beta 1 was.

Compared to the original developer beta, this new public beta now includes some improvements to the Photos app, including the ability to sort albums by date or title, and the ability to add location to images. In version 3 developers gained access to editing extensions. There’s also a change to Two-Factor Authentication.

You should see updates to the public beta builds every few weeks.

Will I be able to update from the beta of El Capitan to the final version?

Beta users will eventually be able to install the "Golden Master" build of the OS on release day without needing to reformat or reinstall.

Can I talk about the beta publicly?

According to Apple and the license agreement all beta testers must agree to, the El Capitan beta is “Apple confidential information.” By accepting those terms, you agree not to discuss your use of the software with anyone who isn’t also in the Beta Software Program. That means 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

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.

Read: How to write apps for the Apple Watch