Upgrades to the Apple Watch Series 9 and second-generation Apple Watch Ultra, which will be detailed at Apple's Wanderlust event tomorrow, will include a new optical heart rate sensor. This is according to a detailed report by Bloomberg's Mark Gurman on everything to expect when Tim Cook takes the stage in Cupertino.

According to Garman, Apple's new wearable changes will focus on "speed, efficiency, and accuracy" with a fourth-generation optical heart rate sensor and a new U2 ultra-wideband chip to enhance the "Find My" experience. the U2 chip will be It is the first improvement for Apple's Ultra Wideband technology since the U1, which was announced with the iPhone 11 Pro. U2 is expected to be included in the iPhone 15 and iPhone 15 Pro. Meanwhile, it is not known what changes the new heart rate sensor will bring beyond simply improved accuracy during workouts.

While sensor and component upgrades will add functionality and precision to the wearables, Garman is confident that the big selling point this year will be performance; with the first new chip since the Series 6 coming in 2020, Apple will be touting a "significant increase in processing speed," He argues that Apple will be touting a "significant increase in processing speed.

A further push to make the Apple Watch category more environmentally friendly also means that change lies ahead. Apple is believed to be attempting to move to a 3D printed device case and is also moving away from silicone watch bands.

While these are the changes mentioned, some things remain very much the same: the Apple Watch Series 9 is expected to maintain its current sizes of 41mm and 45mm, while the Apple Watch Ultra 2 will continue to offer a single size of 49mm.

Both are expected to maintain the same exterior design as their predecessors, paving the way for the Apple Watch X to change things up next year. But if you're eyeing the Ultra 2 but want it in a new color, you're in luck: the Apple Watch X will be available in a new color.

Should you upgrade to the Apple Watch Ultra 2? Here's what my colleague Kate Kozuch, who has used the Apple Watch Ultra for nearly a year, has to say.

Of course, you don't have to wait long at this point to find out what the next generation Apple Watch will look like. Apple's September event is scheduled to begin tomorrow, September 12, at 1:00 PM ET (10:00 AM PST). Here's how to watch it and follow all the announcements.