Anthropic isn't ready to let regular users look at its supposedly super-powerful Claude Mythos AI model just yet. But the AI company has just released an upgrade to its flagship product, Claude Opus — now in its 4.8 version. "It builds on Opus 4.7 with improvements across benchmarks, and is a more effective collaborator," Anthropic promised in a press release Thursday. Indeed, the benchmark numbers, below, show very minor improvements across the board.