Grok 4.8 Release Date: 2.5T Model, What Musk Said (Oct 2026)

Grok 4.8 has no release date yet, but every signal points to it being xAI's next model. Elon Musk described it on X on September 14, 2026 as "a 2.5T model trained with our new C++ software stack" that would "finish training this week and start RL." Reinforcement learning is the last stage before a release.

We track every Grok 4.8 claim on this page and will update the same URL the day it ships. For the bigger picture, see our Grok 5 release date tracker.

1. Grok 4.8 release date: confirmed vs claimed

2. When will Grok 4.8 come out?

xAI has been shipping about one model a month: Grok 4.6, then Grok 4.7 on September 21, 2026, one week after Musk's Grok 4.8 post. If pre-training wrapped in mid-September, a few weeks of RL and safety work would put Grok 4.8 in late October to November 2026. Prediction markets earlier this month put the odds of a launch before November near 57%.

Musk's own timelines often slip. Grok 5 was promised for late 2025, then Q1 2026, and is still in training. Treat any date as a forecast until xAI's news page or the API model list shows grok-4.8.

3. Grok 4.8 specs: what Musk said

The C++ stack is the new part. It is xAI's rewritten training software, and Grok 4.8 is the first model trained on it. Musk has not said whether 2.5T counts total or active parameters, or how the model is split. He also said xAI needs to fix multimodal performance, so image and video input are the area to watch.

4. Grok 4.8 and Grok Bot

On October 7, 2026 Musk said most @Bot requests on X will be "handled by a lightning-fast version of Grok 4.8 when that comes out." So Grok 4.8 will likely show up first as a speed upgrade inside Grok Bot and X, not only as a new option on grok.com.

5. Grok 4.8 vs Grok 4.7

Grok 4.7 is what you can use today: a new larger base model, extended RL on long tasks, a 500K-token context window and API pricing of $2 / $6 per million tokens. Musk himself said 4.7 is "roughly on par with Opus 5.0" and that 4.8 will be a noticeable step up. No head-to-head scores exist yet.

Grok 4.8 status: still not out (Nov 5, 2026)

As of November 5, 2026 xAI has not released Grok 4.8. The xAI news page still lists Grok 4.7 (Sep 21) as the latest model, followed only by Grok Voice 3.0 on Oct 14. Nothing new has shipped in the API model list either.

The latest word came from Musk on October 30. Replying to a post that said xAI "barely has any SOTA models" apart from voice, he wrote on X: "I know it's taken longer than expected, but Grok 4.8 will not be a disappointment. We're not optimizing for benchmarks and I really don't care how Grok does on those, but it will be incredibly useful." The post passed 990,000 views.

• Delay admitted: "longer than expected" means the late-October window most people expected has passed.
• Benchmarks downplayed: expect xAI to pitch real-world usefulness, not leaderboard wins, at launch.
• Grok Bot first: the Oct 7 plan for a fast version to handle most Grok Bot requests still stands, so speed may be the first thing users notice.
• No date: neither xAI nor Musk has named a day. Community polls this week rank it against GPT-6.2 Astra, Claude Fable 5.5 and Gemini 4 Carbon for who ships next.

6. Where Sumus fits

Yes, you can work with Grok-style AI now instead of waiting. Sumus gives your team AI employees that run on top models, Claude, GPT, Gemini and more, inside one group chat. Hand them research, drafts and monitoring today, and switch models as new ones like Grok 4.8 land.

What we're watching

• grok-4.8 showing up in xAI's API model list or release notes.
• A Musk post confirming RL is done.
• Grok Bot speed changes on X that hint at the fast Grok 4.8.

Sources

• Elon Musk posts on X, Sep 14 and Oct 7, 2026
• xAI news and Grok 4.7 launch post, Sep 21, 2026
• Prediction-market and community reports, Oct 2026. Read Oct 29, 2026.