Sony's WF-1000XM4 looks likely to be released in 2021, based on the leaked design. Now, documents filed with the Korean version of the FCC suggest that this may not be the only new Sony headphone to be released in the near future.

As reported by the Walkman Blog, Sony has filed a new "low-power wireless device" with the Korean Communications Commission, using a similar codename to the WF-1000XM4 wireless earphones.

Specifically, the product code for this new device is YY2952. Sony headphones previously used a code with the prefix "HDX". However, this apparently changed for the WF-1000XM4, which we know from previous leaks has the code name YY2948.

Also, while the application does not specifically mention headphones or earbuds, the phrase "low-power wireless device" could refer to using a Bluetooth connection as opposed to a power-hungry wireless system such as Wi-Fi. The application also refers to the product as a "wireless device for wireless data communication systems," which may refer to the ability to use the wireless headphones as a talking headset by pairing them with a telephone.

Combined with the similarity of the product code to the WF-1000XM4, it is fairly certain that these are new wireless headphones. Given that Sony filed the application on May 17, there is plenty of time for a late 2021 release.

However, it is not clear exactly what kind of wireless headphones this device will be. Since Sony's flagship earbuds, the WF-1000XM4, which is supposed to compete with the AirPods 3, are already available, perhaps it will be a follow-up to a less expensive pair like the Sony WF-SP800N. This seems unlikely, though, given that Sony recently released a new white version.

"YY2952" sounds like it could be a direct follow-up to the budget on-ear Sony MDR-ZX220BT with product code HDX-2852. However, this may not be how Sony's new coding scheme works, as the WF-1000XM4's YY2948 code has little in common with the preceding Sony WF-1000XM3 code HDX-2916.

At least the WF-1000XM4 appears to be more imminent, but we will have to wait and see on this one.