On September 13, Elon Musk announced on X that xAI's next model will be Grok 4.8: 2.5 trillion parameters on an in-house C++ software stack rebuilt from scratch, moving straight into reinforcement learning once the main training run completes. The announcement effectively supersedes Grok 4.7 (2.1T), which missed multiple release windows and was publicly downgraded by Musk to 'roughly comparable to Anthropic's Opus 5.0'.

No model card, benchmark table, pricing, API identifier, or release date has been published; every figure attached to Grok 4.8 is a founder claim, not a shipped specification.