The first entry is always the pin's source. Overall confidence is a weighted average of how firmly each reference supports the start and end times used above; a reference counts half as much for every 180 days older than the newest.
No source gives an exact on-sale day. Sony's own press release of September 7, 2026 (https://sony.mediaroom.com[2]/2026-09-07-Sony-Electronics-Introduces-WH-1000XM4C-M4-2nd-Gen-Wireless-Noise-Cancelling-Headphones-and-Updates-Popular-Mid-and-Entry-Level-Wireless-Headphones-with-WH-CH730N-and-WH-CH530) says only that the WH-1000XM4C 'will be available in Black and Platinum Silver this fall'; retail coverage narrows it to September 2026 with deliveries quoted September 23 - October 1. Dated to the last day of the stated month, September 30, 2026, as an estimate.
Sony's[1] own press release confirms it introduced the WH-1000XM4C headphones, with a 10-band EQ, on 7 September 2026 - one day before the pin's stored 8 September 2026 date, consistent with a roundup compiled shortly after.
Engadget's own headline and 7 September 2026 publish date report Sony[1] reviving the WH-1000XM4 as a refreshed $300 headphone option, closely matching the pin's stored 8 September 2026 date, though the page itself could not be fetched to quote directly.
What Hi-Fi?'s launch news says "The biggest change is to the battery" to meet EU regulation (EU) 2023/1542, and that "the 40mm driver of the original carries over to XM4C, as does the DSEE Extreme processing engine and the HD Noise Cancelling Processor QN1".
Something missing or wrong? Say it in your own words: a link that backs this pin up, a different start or end date and why, or a fact it lacks or gets wrong. The AI checks it against this pin's sources, searches for better ones, and adds any page that backs you up. The pin's own sources still count most. A picture that shows something else, or shows it badly, is looked at too, and moved down or replaced.
