In just four days, Apple's It's Glowtime event will kick off (here's how to watch it), and it'll officially announce the iPhone 16 lineup. The newest iPhones will come equipped with iOS 18 already installed. But if you're not upgrading to one of the newer models this fall, you may find that your current phone's operating system isn't supported by Apple. If you are updating, here's when the iPhone 16 models are expected to hit stores.

Generally each year, some older iPhone models are removed from Apple's iOS eligibility list. Last year, for instance, the iPhone 8, iPhone 8 Plus and iPhone X were left off the compatibility list. That meant those iPhone owners couldn't update to iOS 17 and missed out on some notable features.

We'll help you find out if your iPhone will support iOS 18 — which is expected to become available in roughly two weeks — as well as Apple Intelligence. Not sure what's coming with the new update? Here's a summary of the biggest announcements from WWDC, including an overview of iOS 18.

iPhones compatible with iOS 18

We have good news: If you had an eligible phone last year when you updated to iOS 17, that device should still be compatible with iOS 18, according to Apple. That means you won't have to buy a new phone to check out most of the new software features.

• iPhone SE (second generation or later)

• iPhone XR

• iPhone XS

• iPhone XS Max

• iPhone 11

• iPhone 11 Pro

• iPhone 11 Pro Max

• iPhone 12

• iPhone 12 mini

• iPhone 12 Pro

• iPhone 12 Pro Max

• iPhone 13

• iPhone 13 mini

• iPhone 13 Pro

• iPhone 13 Pro Max

• iPhone 14

• iPhone 14 Plus

• iPhone 14 Pro

• iPhone 14 Pro Max

• iPhone 15

• iPhone 15 Plus

• iPhone 15 Pro

• iPhone 15 Pro Max

Put another way, if you have an iPhone from the 2017 model year or earlier (iPhone 8 or iPhone X), you can't upgrade to the latest iOS, but your phone should continue to work — albeit without the latest bells and whistles.

Is your iPhone compatible with Apple Intelligence?

While your older device will still be able to support the latest iOS, chances are that you won't get to try the Apple Intelligence beta yet. Unless you have an iPhone 15 Pro or iPhone 15 Pro Max — the top-end 2023 models — your iPhone isn't eligible. It's a safe bet that the new iPhone 16 models will be fully Apple Intelligence compatible, but we'll have to await the official details at the September 9 event.

iOS 18 new features to expect

While Apple Intelligence is by far the biggest update coming with iOS 18, its features are going to be released more piecemeal over the subsequent few months. And the more advanced features won't be available on older iPhone models aside from the iPhone 15 Pro series. But the rest of the iOS 18 features will hit the handsets listed above. Here are just some of the highlights you can expect when you download Apple's new software later this month.

Passwords app: Securely store all your credentials in one place, including passwords and security alerts that you can access directly in the app. (While this functionality currently exists in Settings, moving it to a new app should make it easier to locate and access.)

Improved Messages app: A new iMessages experience is bringing the option to bold, italicize, underline and strikethrough your text. You'll also be able to add animations to your text messages. The update is also bringing RCS to iPhones to better support Android compatibility.

An organized photos library: The Photos app is getting a redesign, which allows you to create and pin your own collections in the app — think "wedding photos" or "trip to Aruba." It removes the current tabbed bottom and leans into a grid layout. The updated carousel view that was touted at WWDC was removed during the beta process.

Personalized home screen layout: You'll finally get the option to rearrange your apps — for instance, you can leave the middle space open to display your home screen photo, and instead have your apps alone the border of the screen. You can also change the appearance of the apps by tinting them with any color, as well as making the apps larger.

There are plenty of other tweaks and improvements to keystone apps like Maps, Calendar, Safari and more. Check out Cherlynn Low's choices for the best hidden features of iOS 18 and its sibling Apple operating system updates, based on the betas released earlier this year.

Is there an iOS 18 beta?

There is, and you can download it now — so long as you're willing to live with the glitches and challenges of beta software. If you haven't already downloaded it at this point, we'd suggest just waiting for the real deal to be released in just a few days.