OpenAI says GPT-6 is much better with legacy programming languages such as COBOL and Fortran

OpenAI improved its latest models for low-resource programming languages like COBOL, Fortran, and Visual Basic. On the new MultiLangBench, GPT-6 Astra hits an 87.4 percent test pass rate across 20 languages, up from about 38 percent for GPT-5.6 Terra. For COBOL migration specifically, GPT-6.1 Sol reaches up to 97.9 percent accuracy, a result that could matter for modernizing critical financial infrastructure.