COBOL is 67 years old and still "supports more than 40% of online banking systems, 80% of in-person credit card transactions and 95% of ATM transactions". GPT-6.1 Sol now scores 98% on evaluation to migrate Cobol programs to modern coding languages. OpenAI says a rewrite only passed its test if every output matched the original byte for byte (because one wrong rounding rule could mess up everyones bank account balances). Still work to be done but “These evaluation results demonstrate progress toward more accurate, affordable code migration for teams modernizing the software their businesses depend on.”