A new report has uncovered compatibility issues with version 2.0 of the Universal Stylus Initiative (USI) standard that means older USI 1.0 styluses won’t work with some newer USI 2.0 devices. ChromeUnboxed came across the problem while using Lenovo’s new Chromebook Duet 3, when it noticed that existing styluses weren’t working with the device.

It seems the problem with the Chromebook Duet 3 is that its screen uses an in-cell design that combines elements of the display with a digitizer that handles stylus input. ChromeUnboxed reports that this is a more compact and cost-effective way to offer stylus input. But because support for the technology was only introduced with USI version 2.0, the Duet 3 doesn’t work with styluses made to work with USI 1.0 displays.

USI chairman Peter Mueller confirmed the limitation in a statement given to ChromeUnboxed. “Because the touch and display driver are more tightly integrated for in-cell, the touch sensing has to occur within certain timing windows in between the display being driven. It is this timing constraint that caused us to have to modify our USI spec for some in-cell panels,” he said. “We spent many months looking at alternatives to ensure backwards compatibility, but it was not doable.”

It’s unclear if the problem affect all USI 2.0-compatible displays, but it’s an unfortunate limitation that seriously restricts the amount of styluses that can be used with devices that use in-cell tech like the Chromebook Duet 3. At the moment, there just aren’t that many compatible styluses on the market, and even Lenovo’s own USI Pen 2 doesn’t appear to be available yet.

The situation risks being confusing for consumers. Mueller says the USI is recommending that vendors take various steps to mitigate this, but it’s unclear how many will follow suit. “We have requested clear documentation and marking, and also shipping with a 2.0 stylus (ideally) in order to minimize the confusion and user frustration,” Mueller tells ChromeUnboxed.

Other features of USI 2.0 include support for styluses that can be charged wirelessly, an expanded color palette, and a broader range of tilt and shading features.

The Universal Stylus Initiative is far from the only organization to have seen its theoretically simple, universal standard hit with compatibility issues. Just look at the confusing mess of standards the USB Implementers Forum currently offers or the issues surrounding HDMI 2.1. Groups like these have to strike a difficult balance between controlling how their technologies can be used to avoid confusion, while leaving them open enough to encourage wide adoption.

Regardless of the reasons, it all unfortunately means you’ll have to continue to play close attention to the fine print, even when a device supposedly supports a universal standard.