LONDON -- Apple is releasing its latest desktop software update on Wednesday and here are the steps you need to take to make sure you can prepare for, download and install it easily.

Mac OS X El Capitan was announced by Apple on stage at WWDC 2015 in San Francisco on Jun. 8 with a slew of new features including improved Spotlight search results; contextual search results in mail and finder; the ability to pin full-screen applications to one side of the screen or the other; and my favorite - the ability to shake the trackpad to find your cursor - especially helpful on larger iMac screens.

Apple has also done a lot of work under the hood, promising that opening apps is 1.4 times faster than last year's OS X Yosemite. Switching between open apps is twice as fast - as is opening new messages - and opening a PDF in the Preview app is four times faster.

OS X El Capitan Apple's latest desktop operating system, OS X El Capitan, can be downloaded through the Mac App Store. Photo: Reuters/Robert Galbraith

Just like Mac OS X 10.9 (Mavericks) and OS X 10.10 (Yosemite), the update to OS X 10.11 (El Capitan) will be free for users.

El Capitan compatibility

First up, a note on compatibility. Apple has said that El Capitan will work with the following devices:

  • 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)

When Can I Download El Capitan?

Apple typically makes new operating system updates available at 1 p.m. ET on launch days. Here are local times around the world:

  • San Francisco - 10 a.m.
  • Dallas - 12 a.m.
  • New York - 1 p.m.
  • Buenos Aires - 2 p.m.
  • London - 6 p.m.
  • Amsterdam - 7 p.m.
  • Jerusalem - 8 p.m.
  • Bangkok - midnight (Thursday)
  • Hong Kong - 1 a.m. (Thursday)
  • Seoul - 2 a.m. (Thursday)
  • Sydney - 3 a.m. (Thursday)

How To Download El Capitan?

There are several ways to access the update when it is available. Clicking on the Apple logo on the top left hand corner of your desktop and tapping  About This Mac and clicking on the Software update button. The other way of accessing the update is by going directly to the Mac App Store which is available through the dock or again directly through the Apple menu.

In the Mac App Store, click on the Updates button at the top of the windows and when El Capitan is available for download it will appear here.

os x el capitan OS X El Capitan running on a MacBook. The new version is forcing Interacto, developer of Flavours, to halt development of their product. Photo: Apple

El Capitan is only available as a digital download through the Mac App Store and not available as a physical disc. If you are running a version of OS X without access to the App Store (OS X Leopard or earlier) luckily you can still buy a physical copy of OS X Snow Leopard from Apple for $20.

Backup Your Data

Before installing any operating system update it is vital to backup all your data so that if anything happens during the installation process you can recover your information. On Macs backups are most easily done using the built-in TimeMachine function which allows you to automatically back up your Mac at regular intervals. Details on how to use TimeMachine can be found here.

Double check your Mac has sufficient RAM (Apple says at least 2GB but ideally 4GB) and enough storage space. Apple recommends 8GB but you should probably have some more as the installer will create some temporary files. You should also make sure to  update to the latest version of OS X Yosemite before beginning an update to the new OS.

Installing OS X 10.11 El Capitan

Once the update goes live, download times are likely to be long as users around the world look to upgrade their systems all at once. If you don't have to have El Capitan straight away, it might be worth waiting  a few hours or even a few days when Apple's servers will be under less stress.

The Yosemite update was 5GB so expect the El Capitan update to be a similar size and judge how long it will take to download based on that and the speed of your internet connecting. Once downloaded the install process is pretty straightforward and Apple has automated almost everything. You will be asked to enter your Apple ID credentials and iCloud password during the process, but once downloaded, the update shouldn't take more than 10 minutes to install.