Apple’s newest operating system, iOS 7, is due to hit the company’s servers Wednesday, meaning that iPhone, iPad and iPod Touch users can get ready for some big changes. Here’s what you should know about the update.

What’s changing: There are a lot of changes in this operating system, including what will be immediately evident upon download: the system’s general look. The new system is flatter and brighter than previous versions of iOS, which have historically had icons with shadows and textures more like the real world — think of the yellow, lined paper in the Notes app. Much of that kind of detailing is gone from this version of the operating system in favor of cleaner design.

Under the hood, there are also quite a few updates. For example, users can now access setting from a central “control center” — similar to the unified notifications screen on Android devices. Core apps have also received makeovers, such as the Photo app, which will let users take advantage of camera filters and take photos in Instagram-friendly squares. In addition, the photos are grouped differently, so that users can see all the snaps they’ve taken in a specific time period or in a certain place grouped together more intuitively.

Other updates include the ability to have apps update in the background — meaning fewer red bubbles for you to deal with — and improvements to Siri that lets you do things such as adjust settings on your phone.

Apple has also added an iTunes Radio feature, similar to Pandora, that will let users make and share playlists based on their personal music preferences.

Who’s eligible: Not all devices support the new system and all of its features. The iPhone 5s, 5c and 5 will all obviously support the latest edition. But the iPhone 4S doesn’t have support for filters in the Camera app or the AirDrop file-sharing feature. Those with the iPhone 4 will be unable to access those features, plus Siri and the ability to take panoramic photos. Older models will not work with iOS 7.

As for iPads, the fourth-generation iPad (released after November 2012) will support iOS 7 in full, as will the iPad mini. The third-generation iPad (released March 2012) , however, has no support for AirDrop, filters in the camera app and panoramic photos.

The iPad 2, as it was originally introduced in March 2011, will also not support AirDrop, filters and panoramic photos as well as square photo and video formats, as well as Siri.

Only the latest version of the iPod touch, meaning those introduced after October 2012, will support the new system.

If you aren’t eligible to download the new system, don’t worry too much. Apple is making allowances for app developers to continue supporting older devices, if they choose.

How to update: Apple now allows users to get their most recent updates over-the-air, meaning that iPhone, iPad and iPod users should be seeing a notification pop on their settings app to let them know that there’s a new update on its way.

To get to that update — whenever Apple launches the new system — you can head to your settings app, and then to the “General” menu. From there, head to “Software Update.” Once the new system is ready to be downloaded, you should be able to get it from this menu.

Should you download immediately?: It’s tempting to download the newest system immediately, but you should note that Apple — like many companies — always has a few bug fixes to make after releasing its first version. Unexpected issues such as problems with WiFi connectivity or battery drain have come with new upgrades in the past, so it may be worth sitting out for a little while until the company can resolve possible issues.