Sony’s WH-1000XM3 over-ear, noise-canceling headphones have been some of the best on the market, with very good noise cancellation, the best sound of any of the WH-1000X series, and improved fit from previous versions. But it appears a new version of Sony’s wireless cans are on way, as filings for what appear to be the WH-1000XM4s just hit the FCC over the weekend.

Unfortunately, there isn’t much we can glean from the filings. Companies often file required documents about new products with the FCC long before the public sees or hears anything about them, and the companies can request the FCC keep some documents confidential, like photos of the product and the user manual. Sony has kept both under wraps with its WH-1000XM4 filings.

The M4 version number seems like the next logical step

We aren’t sure if WH-1000XM4 is the actual name of the next version of the headphones, but based on some information about the filings, M4 seems likely to be the next version number. The WH-1000XM3s had the FCC product ID of AK8WH1000XM3 (emphasis mine), and the new version’s product ID is AK8WH1000XM4 (emphasis mine). And the previous three generations had the version numbers of M1, M2, and M3. So the M4 version number seems like the next logical step.

The filings don’t give any indication of when the new headphones might come out, and something hitting the FCC now can still be some time away from release. But CES is next month, so perhaps Sony will announce its successors to the M3s at the Las Vegas show.

If you’re in the market for wireless headphones right now, the M3s are still a great option, and they are even on sale at some places as of this writing. Typically, the M3s are $349.99, but I see them for $278 at Amazon and Walmart, and $279.99 at Best Buy and Target.