Ahead of the launch of Windows 8.1 on 18 October, Microsoft has officially detailed how it plans to launch the massive operating system update to the masses. 

Microsoft will make Windows 8.1 available to current Windows 8 users for free. Windows 7 users and below looking to jump on the Windows 8.1 train will need to purchase the base software for $119.99 (£75) and Windows 8.1 Pro for $199.99. If you want to make the jump to Windows 8.1 Pro from just plain Windows 8.1, you'll have to shell out $99.99.

The $119 pricing and above is a "download that does not require a previous version of Windows in order to be installed". New computers and other devices will come pre-installed with Windows 8.1 from 18 October.

Microsoft says Windows 8.1 will officially be available starting at 12:00am on 18 October in New Zealand, which is 4:00am PST, 7:00am EST, and 12:00PM BST on 17 October.

Windows 8.1 offers a host of improvements, additional features and the return of the start button. A preview build is currently available to download should you want to try it out before the official release day. We've given you a full run-down of what to expect.