Originally scheduled to launch to the public today, watchOS 2 will arrive later than intended, due to the discovery of a bug in the software, Apple has confirmed.

The bug is taking Apple "a bit longer to fix than we expected," company said in a statement to TechCrunch. It said the software update will be released "shortly," but did not provide a specific timeframe.

Still apparently on track to be released today, however, is iOS 9, Apple's next-generation software update for iPhone, iPad and iPod touch.

Originally unveiled by Apple in June, watchOS 2 has been in beta testing for developers since the Worldwide Developers Conference. Unlike with iOS 9 and OS X 10.11 El Capitan, there has not been a public beta for watchOS 2.

The highlight feature of the new Apple Watch operating system is the ability for third-party apps to run natively on the wrist-worn device. This should allow software to run more quickly and operate more independently of the iPhone.

watchOS 2 also enables developers to create their own watch face complications. These will offer users the ability to add glanceable information, such as upcoming flights or sports scores.

Complications will also feature a new capability called "Time Travel," where users can rotate the Digital Crown on their Apple Watch to see information for later in the day, including calendar entries, weather, and more.

Apple also has a new feature called nightstand mode, which allows the Watch face to be viewed on its side for charging. When resting like this, the Digital Crown and side button can be used to snooze and end an alarm in the morning.

Friends can also be added more easily to favorite contacts in watchOS 2.

Siri will also be able to start workouts, without a user needing to touch the Watch to begin an activity. And third-party workout apps will be able to run natively on the device, and workouts will count toward goals in the Activity app.

Apple Pay on watchOS 2 will also include store cards and rewards cards, just like in iOS 9. Mass transit capabilities in Maps will also work on Apple Watch with the next-gen operating system.

Developers creating apps for watchOS 2 will also be able to access the Apple Watch's microphone, or play audio out of the device's speaker. The new operating system will also offer access to HealthKit, give the ability to show video, read accelerometer data, and more.