Claude Opus 5.1 Release Date Rumors: Is Anthropic’s Big Upgrade Coming Soon?
Claude Opus 5.1 Release Date Rumors Heat Up — Is Anthropic About to Drop Its Opus 5 Fix? Claude Opus 5.1 could be waiting in the wings—and AI fans think Anthropic may unleash it sooner rather than later. The rumor mill is working overtime after two mysterious model identifiers— “claude-marshmallow-eap” and “claude-melon-eap” —reportedly appeared in third-party developer tools and online testing circles in late August. Some Claude watchers believe Marshmallow could become Claude Opus 5.1 , while Melon may represent a future Sonnet or Haiku update. But before everybody starts popping the digital champagne, Anthropic has not confirmed what...