What does the 2.5 update actually add?
Teenage Engineering has a habit of treating its boxes like living products, and the EP-133 K.O. II just got its most useful upgrade yet. OS 2.5, out 24 June 2026 and free for everyone who already owns one, leads with class-compliant USB audio. That means you plug the K.O. II straight into a computer or phone and get stereo audio in, usable both as a live source and as something to sample, plus stereo audio out to record your patterns directly into a DAW. On a sampler this pocketable, losing the separate audio interface is a genuine workflow change.
Around that sit the features owners have asked for since launch. There is finally an arpeggiator, in oneshot and legato modes. Samples can be reversed from the Sound Edit page. Equal-length auto-chop slices a loop into even pieces in one move. You can pick your recording quality, mono sampling time jumps from 20 to 40 seconds, and there are quieter wins across timestretching, sample cropping, a live playback-position readout and a pile of bug fixes.
Why does USB audio matter on a box this small?
The K.O. II always punched above its size, but getting clean audio in and out meant cables, adapters or a separate interface. Folding that into the firmware turns it from a sketchpad into something you can finish a track on. Sample a stem off your laptop, chop it, sequence it, then bounce the result back over the same cable. For producers who travel light, or who use the K.O. II as the fun, tactile front end to a software setup, this is the missing link.
Two years in, Teenage Engineering is still adding the features people actually asked for, for free. That is rarer than it should be.
Is the K.O. II still worth it in 2026?
The gripe will be timing: arpeggiator and USB audio are things plenty of buyers wanted on day one, and the wait was long. But the counterpoint is simple. A sampler you bought in 2024 is materially more capable today and cost you nothing extra. In a market where new hardware lands every week, a brand that keeps deepening the thing you already own earns the loyalty.
