The delayed watchOS 2 from Apple is finally available to download, Digital Spy reports.

Users of the Apple Watch operating on iOS 9 can update to watchOS 2 starting from September 21.

In order to download the update, just open the Apple Watch app, click through to General and follow the instructions under Software Update.

Scheduled to roll out last Wednesday (September 16), watchOS 2 was delayed at the last minute by Apple because of a technical glitch.

"We have discovered a bug in development of watchOS 2 that is taking a bit longer to fix than we expected. We will not release watchOS 2 today but will shortly," an official Apple spokesperson told Digital Spy at the time.

Introducing a number of new features and functions, watchOS 2 will enable existing Apple Watches to run new third-party apps, offer photo-based backgrounds and run a new Nightstand mode.

While the unveiling of watchOS 2 was delayed by five days, Apple's iOS 9 update still rolled out as planned last Wednesday.