Apple has just released iOS 8, and you should be able to download it now or momentarily. But if you’re preparing to update your iPhone or iPad, then be ready to clear out enough free space.

To see if iOS 8 is available for your device, just visit Settings > General > Software Update on your Apple mobile device. Your device will then check to see if the latest version of Apple’s mobile OS is ready for download. Apple may not roll out the update to all users at once, though, if you’re not given the option just yet, keep checking back every few minutes.

As always, iOS 8 is a free upgrade for iPhone, iPad and iPod owners. The eligible devices are iPhone 5s, iPhone 5c, iPhone 5, iPhone 4s, iPod touch (5th generation), iPad (third and fourth generation), iPad 2, iPad mini, iPad mini with Retina display and iPad Air.

iOS 8 requires up to 5.7GB of free space to install. The required space varies depending on device and increases up to 7GB on some iPad models. However, if you have an 8GB iPhone 5C or even a 16GB iPhone, and then you’re likely to run into issues.

There’s no easy fix to free up space quickly yet, you can use the iTunes client on Mac or PC to update a device to avoid the huge space requirement. Though the iTunes method yet requires free space, not nearly as much as 5GB using the over-the-air upgrade method on the device.