AI illustration: Grok 4.8 finishes training this week (by Sep 20, 2026)
xAIAI
Missed

Grok 4.8 release date: training due Sep 20, 2026, missed

Elon Musk said Grok 4.8 would finish training by Sep 20, 2026. The deadline passed and it didn't happen.

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“Grok 4.8, which is a 2.5T model trained with our new C++ software stack, will finish training this week and start RL”
— Elon Musk · Sep 13, 2026 · @elonmusk on X, Sep 13 2026 evening CT ↗
See his original post on XLoads Elon's actual tweet, right here.
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What actually happened

Deadline Sep 20 2026 passed with no public receipt that Grok 4.8 finished training. Fetched Oct 13 2026: docs.x.ai/docs/models has no grok-4.8 id; flagship listed is still grok-4.7. Training-complete is an internal milestone with no public receipt. Missed; watch to flip missed → delivered-late if xAI/Elon confirms training finished / RL started, or any public 4.8 ships (L13). docs.x.ai/docs/models fetched Oct 13 2026 — no Grok 4.8; grok-4.7 still listed ↗

The Progression

Sep 13, 2026
The promise: “Grok 4.8, which is a 2.5T model trained with our new C++ software stack, will finish training this week and start RL” · @elonmusk on X, Sep 13 2026 evening CT ↗
Sep 20, 2026
Deadline passed. Deadline Sep 20 2026 passed with no public receipt that Grok 4.8 finished training. Fetched Oct 13 2026: docs.x.ai/docs/models has no grok-4.8 id; flagship listed is still grok-4.7. Training-complete is an internal milestone with no public receipt. Missed; watch to flip missed → delivered-late if xAI/Elon confirms training finished / RL started, or any public 4.8 ships (L13). docs.x.ai/docs/models fetched Oct 13 2026 — no Grok 4.8; grok-4.7 still listed ↗
Today · Oct 14, 2026
Status: Missed · 24 days past due. Never happened.

On the evening of September 13 2026, Elon Musk replied that Grok 4.8 — a 2.5T model on xAI's new C++ software stack — will finish training this week and start reinforcement learning. That dates a near-term Grok 4.8 training-complete milestone to about September 20 2026, separate from the Grok 4.7 release card.

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Receipts

LAST CHECKED 2026-10-13

xAI’s record

Delivered
15
68% of resolved claims delivered.
Missed
7
Deadline passed, still no-show.
Still open
19
On the clock now. All 41 xAI claims →

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