You don't have to be a genius to predict that Apple is likely working on an update to the Powerbeats 3 earbuds, and yet if you want to see evidence that a follow-up is actually on its way, 9to5Mac says it has spotted proof in iOS 13.3.
Apple released the iOS 13.3 update on 10 December. Strings of code found within the software suggested Powerbeats 4 are coming soon with the ability for you to talk to Siri simply using the "Hey Siri" wake phrase. 9to5Mac speculated the Powerbeats 4 are imminent and likely feature Apple’s proprietary H1 chip for seamless connectivity with different devices, as well as for improved battery life.
With Apple’s H1 chip, the Powerbeats 4 would most likely also support the “Announce Messages with Siri” feature, which allows Siri to read messages aloud without you unlocking your iPhone. Keep in mind Apple currently sells the Powerbeats Pro with “Hey Siri” support. The Powerbeats 4 will likely end up being a lower-priced option for you to consider when shopping Apple's earbuds.
The Powerbeats 3 are "wireless" in-ear headphones with a wire between each bud. They sell for around $199 at Apple and other retailers. Meanwhile, the PowerBeats Pro earbuds cost around $250, and they're completely wireless. There’s no word on when Apple will release the Powerbeats 4, but 9to5Mac said iOS 13.3 has implied their release will be "sooner rather than later".
9to5Mac also found evidence of the AirPods Pro in iOS 13.2 right before their release, so it's worth paying attention to this particular discovery.