Grok 4.20 was released by xAI on February 17, 2026, as a flagship model in the Grok line.
xAI's new flagship Grok: the first version that retrains itself every week from real-world feedback, and in March 2026 it held the record on Artificial Analysis's test for admitting it doesn't know instead of making up an answer.
Compared with Grok 4.1 · the version it replaces
Retrains itself every week from real-world feedback
Update cadence — how often the model is refreshed
weekly
✦ new in Grok 4.20 · first Grok to do this
When it didn't know an answer, it said so 78% of the time instead of making one up
Artificial Analysis Omniscience test — how often it admits not knowing
78%
✦ a record when reported in March 2026 · other models have beaten it since
Scores higher than Grok 4.1 when people compare answers blind
Arena Text leaderboard — people pick the better answer without knowing the model
1475
▲ up from 1465 for Grok 4.1 Thinking · +10 Elo · #34 on Arena, Sep 2026
Every Monday, only when something shipped: the AI models that came out, what each one changed, and which lines are due next.
We email you a link to confirm first · unsubscribe anytime · read past issues · about the newsletter · RSS for the Grok line
Grok 4.7 is the current model in this line. The card shows how long it has been since the last release against the line's usual gap and its recent ones — the rhythm, not a date.
Latest: Grok 4.7 · Sep 21, 2026
“Grok 4.8, which is a 2.5T model trained with our new C++ software stack, will finish training this week and start RL” — xAI, Sep 14, 2026 · Elon Musk on X
What changed in Grok 4.7 →Newest first. See the full line with every card →