OpenAI says GPT-6.1 Sol hits 86.6% on COBOL migration test

OpenAI reported that GPT-6.1 Sol reached 86.6% accuracy on its COBOL migration evaluation at low reasoning effort, up from 5.4% for GPT-5.6 Sol, at 39% lower cost, and 97.9% at higher effort. The COBOL test details remain unpublished; only the MultiLangBench suite is open, where GPT-6 Astra scored 87.4% versus 26.8% for its predecessor.

• GPT-6.1 Sol scores 86.6% on COBOL migration at low reasoning, 97.9% at high
• Migration cost dropped 39% versus GPT-5.6 Sol
• MultiLangBench: GPT-6 Astra hits 87.4% vs 26.8% for GPT-5.6 Sol across 20 languages
• COBOL evaluation is not public, so results can't be independently verified