This might be why you can't download iOS 9 straight away

Apple released their updated operating system this evening, but many iPhone users have found that downloading it hasn’t been as easy as it was in the past.

After opting to download the update, many apple users have been greeted with a vague error message.

#iOS9 is such a tease. pic.twitter.com/liZC8Zae3K

— Denise O'Donoghue (@deniseodonoghue) September 16, 2015

The reason for this could be simple: Apple have developed a queue for the download.

TechCrunch reports that Apple has implemented a queuing system for major updates such as iOS 9. Downloading the update itself takes just a few minutes, but it could take several hours before the actual download starts.

While you wait for the download, check out these seven core features of iOS 9 and how to prepare your devices before the download begins.