The iPhone 7 will not have a traditional headphone socket.
Apple said its lightning connector could be used instead, which would make room for other components. It will also promote the use of wireless earphones, and has released a set of its own called Airpods.
The firm said it had taken "courage" to take the step.
However, it risks annoying users who will now require an adapter for existing headphones.
The US company unveiled its latest handsets at an event in San Francisco following a year in which its phone sales and market share shrank.
"The current difficulties with the EU will have little bearing towards the iPhone 7 at this juncture," predicted Ben Wood from the CCS Insight consultancy.
"But the dispute will drag on for years, and if sentiment turns against Apple that could have major implications for the brand.
"For now, there's a strong argument that the iPhone 7 is more than an iterative update.
"Upgrades are all important to Apple and for consumers coming from an iPhone 5S or iPhone 6, the iPhone 7 will feel like a considerable step up."
Airpods
The 3.5mm headphone jack was made popular by Sony's Walkman cassette players, but was first introduced in one of the Japanese company's transistor radios in 1964.
Apple has repeatedly been willing to ditch connectors and other ageing tech from its products earlier than its rivals.
However, it was not first in this case.
"Lenovo's Moto Z and select models from Chinese manufacturer LeEco have launched without the 3.5mm socket in 2016," noted IHS's Ian Fogg.
"These manufactures have had little adverse reaction, in part, because they sell many fewer smartphones than Apple."
One audio expert also had doubts.
