New OpenAI Model Keeps Old COBOL Code Working in 98 Percent of Conversions

OpenAI reported on October 26, 2026 that GPT-6.1 Sol kept old COBOL code, an ancient programming language, working the same in 98 percent of conversions when told to think harder. On lower settings, it scored 87 percent. On those same settings, GPT-6 Sol scored 21 percent and GPT-5.6 Sol 5 percent. A conversion counts only if every check passes.