Safeguards: upcoming dates

Recent

• AI09/28/2026@TechDesk

  Claude Sonnet 5.5 Released

  San Francisco, California, United StatesAnthropic

  

  Starts 09/28/2026CONFIRMEDDate confidence: CONFIRMEDStated as firmHow firmly the source words the date: confirmed, scheduled, estimated, delayed or unverified.Show all CONFIRMED pins86% CONFIDENCEOverall confidence: 86%How well the pin's source and references back up its dates.Weighted average of how firmly 6 references, the source included, support the pin's start and end times; a reference counts half as much for every 180 days older than the newestShow all pins at 75% confidence or better4 days agoAnthropic's^[1] announcement is headed "Claude^[4] Sonnet 5.5 September 28, 2026" and says it "is now available on all platforms"; the model page lists "Released September 28, 2026", and TechCrunch^[2] (11:00 AM PDT, September 28, 2026) and CNBC^[3] ("Anthropic on Monday released") agree.

  Anthropic releases Claude Sonnet 5.5, the second model in its Claude 5.5 family, which it says runs more than 30% faster than Sonnet 5 and costs up to 30% less per task at the same $2 and $10 per million token prices.

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• AI09/22/2026@TechDesk

  Claude Opus 5.5 Released

  San Francisco, California, United StatesAnthropic

  

  Starts 09/22/2026CONFIRMEDDate confidence: CONFIRMEDStated as firmHow firmly the source words the date: confirmed, scheduled, estimated, delayed or unverified.Show all CONFIRMED pins90% CONFIDENCEOverall confidence: 90%How well the pin's source and references back up its dates.Weighted average of how firmly 4 references, the source included, support the pin's start and end times; a reference counts half as much for every 180 days older than the newestShow all pins at 75% confidence or better10 days agoUnlike the Fable 5.1 announcement, this page dates itself: the header reads “Claude^[2] Opus 5.5 September 22, 2026”. TechCrunch's^[3] byline (“9:30 AM PDT · September 22, 2026”, “released on Tuesday”) and XDA's 2026-09-22T16:44Z timestamp agree, so the source^[1] keeps the claim and the two reports corroborate it.

  Anthropic releases Claude Opus 5.5, the first model in a new Claude 5.5 family, which it says matches Claude Fable 5.1 on most work while costing 40% less to run than Opus 5.

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• AI09/22/2026@TechDesk

  Claude Fable 5.1 and Mythos 5.1 Released

  San Francisco, California, United StatesAnthropic

  

  Starts 09/01/2026CONFIRMEDDate confidence: CONFIRMEDStated as firmHow firmly the source words the date: confirmed, scheduled, estimated, delayed or unverified.Show all CONFIRMED pins90% CONFIDENCEOverall confidence: 90%How well the pin's source and references back up its dates.Weighted average of how firmly 5 references, the source included, support the pin's start and end times; a reference counts half as much for every 180 days older than the newestShow all pins at 75% confidence or better31 days agoThe announcement page does not date itself - it says only “September 2026” and “available today”, and the one ISO timestamp in its HTML is a page build time. The date comes from Anthropic's^[1][3] own news index, whose card for this article carries <time>Sep 1, 2026</time>, and is confirmed independently by MacRumors^[5]' article:published_time of 2026-09-01T19:15:16Z (“Anthropic today introduced Claude^[2] Fable 5.1”) and by Wikipedia's^[4] Claude Mythos infobox, “Claude Mythos 5.1 / September 1, 2026”.

  Anthropic releases Claude Fable 5.1 and Claude Mythos 5.1 - the same model behind different safeguards - and cuts cache reads by 75%, making typical workloads about 25% cheaper to run than Fable 5.

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