Apple Inc.’s most important new product unveiling of the year gets underway on Tuesday, when the company will introduce the iPhone 15, new smartwatches and the latest AirPods.

The event kicks off from the company’s headquarters in Cupertino, California, on Sept. 12 at 10 a.m. local time.

The most significant new product will be the iPhone 15 Pro line, with more minor refreshes coming to the Apple Watch and the AirPods. The company also is likely to discuss iOS 17, iPadOS 17 and watchOS 10, its upcoming software updates for the iPhone, iPad and Apple Watch.

The event, dubbed “Wonderlust,” won’t introduce a flashy new product category — like the Vision Pro headset unveiling in June — but the combination of the iPhone, Apple Watch and AirPods remains the core of the company’s ecosystem. Together, those products bring in roughly 60% of overall revenue, excluding the money generated by accompanying digital services like Apple Music.

The stakes are high this year. Apple is looking to pull out of a sales slump, and it’s counting on major changes to its high-end iPhones to get people to upgrade. The company also is facing trouble in China, where government workers are increasingly banned from using its devices and consumer sentiment may be turning against US technology.

Another wrinkle this year: Apple is switching the phone’s charging and data port to the USB-C standard, a move that may improve performance but potentially irk consumers. This will mark the second time the iPhone’s port will change. The last switch came in 2012 when Apple moved from the 30-pin iPod connector to Lightning on the iPhone 5.

Here is everything to expect from the event, based on Bloomberg’s reporting and people familiar with the company’s plans:

The iPhone

• Keeping with its usual pattern from the past few years, Apple is planning to debut four models: the iPhone 15, 15 Plus, 15 Pro and what will be called the 15 Pro Max (not Ultra as some have speculated). The regular iPhone 15 and 15 Plus will be the base models, featuring aluminum sides and a glass back like the iPhone 14 and 14 Plus. The two high-end iPhones, meanwhile, will feature a new design that switches the side material from stainless steel to titanium.
• The iPhone 15 and 15 Plus will continue to use 6.1-inch and 6.7-inch displays, but the screens on the iPhone 15 Pro and Pro Max will appear ever so slightly larger. The look is part of a noteworthy change to the pro models: Borders around the screen will be about one-third thinner. To create the slimmer bezels, Apple is using a new manufacturing process called LIPO, or low-injection pressure overmolding.
• The titanium on the Pro phones has a brushed look and replaces the fingerprint-prone steel used since the iPhone X line. People with knowledge of the new devices say the switch to titanium makes the phone more durable and about 10% lighter. The devices will retain the frosted glass back of current models, but the edges connecting the side and front are now less sharp than before.
• While the non-Pro phones will look mostly like current models, they will get one major visual change: the Dynamic Island, an interface that was first added to the iPhone 14 Pro models last year. It lets users see alerts in an area at the top of the display.
• The higher-end phones will have a performance edge, keeping with Apple’s approach in recent years. This year’s Pro models will get a faster A17 chip built on the new 3-nanometer production process and additional memory. The processor will make those models snappier, but the biggest enhancements are the battery life savings. The iPhone 15 and 15 Plus will get the slower A16 chip from last year’s Pro phones.
• The regular iPhone models will get a significant camera improvement, moving from a 12-megapixel main camera sensor to a 48-megapixel version. That matches the resolution of the main camera on last year’s iPhone 14 Pro.
• The iPhone 15 Pro models will continue to have three cameras, including a 48-megapixel sensor. There are new telephoto and ultrawide lenses with more megapixels than in last year’s Pro sensors, and the company is planning to tout the enhancements as the premier additions in this year’s phones. The biggest camera upgrade will come exclusively to the iPhone 15 Pro Max: an updated telephoto system with enhanced hardware zoom capabilities. This will double the iPhone’s ability to zoom into images — with the physical lens itself, rather than software — from 3X magnification to around 6X.
• All of the new iPhones will get a “U2” ultrawide-band semiconductor, the first new Apple UWB chip since the U1 launched in the iPhone 11 Pro in 2019. The new component is expected to improve location capabilities, making it so people and devices can be tracked more accurately in the Find My app. Apple plans to add this chip to the next versions of all of its major products.
• The four new models will also switch from Lightning to USB-C for wired charging and data transfers, but increased transfer speeds will be reserved only for the Pro models. All of the phones will gain faster wireless charging.
• The Pro phones will replace the ring/mute switch for the first time since the feature launched with the original iPhone in 2007. The switch is becoming an “Action Button” that can be customized to handle a variety of functions, including silencing the phone, turning on a Focus mode, opening the flashlight, launching the camera, starting a voice recording, opening Siri shortcuts, pulling up the digital magnifying glass and opening accessibility settings.
• The inside of the iPhone 15 Pro models has been redesigned to match the revamped aluminum chassis from the regular iPhone 14 (iFixit has a rundown of the changes). That overhaul makes the phone easier to repair.
• Apple has some new colors up its sleeves for both phone lines. The regular models will come in pink, black, white, blue and yellow, while the Pro phones will come in gray, black, dark blue and white. The company is also discontinuing leather cases in favor of a more environmentally friendly material.

Apple Watch

• The company is planning two updated lines: the Apple Watch Series 9 — available in the current 41-millimeter and 45-millimeter sizes — as well as a second-generation Ultra, which sticks with the 49-millimeter size.
• All of the new Apple Watches will look like last year’s models. That means that the standard watches will have the same basic design as the Series 4 introduced in 2018, while the Ultra keeps last year’s inaugural look. The company is planning new materials and colors, though, including the use of more recycled metals and a black Ultra option.
• The big focus for the Apple Watch this year will be performance, with the company planning to heavily tout major gains in processing speed. The watches will get their first new chip since the Series 6 got a processor jump in 2020.
• Like the iPhone 15 line, the new watches will get the U2 ultrawide-band chip for improved Find My capabilities.
• The watches will also get various sensor and internal component upgrades with a focus on speed, efficiency and accuracy, including a new version of Apple’s optical heart rate sensor.
• The company is testing a shift to 3D-printed device cases, starting with the stainless steel models of the Series 9. Apple is planning to shift the second-generation Ultra to this process next year as well. This comes as part of a major environmental push for the watch planned for this year.
• As part of that effort, Apple is shifting away from some of its leather watch bands. Signs of that change are already emerging: The company recently cut prices by up to 90% on some of its leather straps and Hermes-branded watch bands in an internal employee store. It has also run out of its stainless steel link bracelets from the 2015 watch, suggesting that the band will either finally get updated or be discontinued.

AirPods

• As part of the switch to USB-C charging on the iPhone, Apple is working to move all of its Lightning-based accessories over to the new standard. One of the first products on that list is the AirPods Pro, a top-selling item for Apple. The company also plans to bring USB-C charging to its low-end AirPods and AirPods Max as early as next year.
• The earbuds won’t get any other major new hardware features, but a software update will bring improved automatic device switching, the ability to mute and unmute from the AirPods themselves, and a new feature called Conversation Awareness that automatically silences media when people begin speaking to the wearer.
• Apple is also working on new health features for AirPods, including body-temperature sensing and a new hearing-test system, but those enhancements are likely to be released later.

Bloomberg News will be covering the event live with news stories and a live blog tracking the announcements.