OpenAI reports a marked improvement in its models' quality on COBOL, Fortran and other "rare" programming languages
Prepared by Sintelligent with the help of SI. Published in SI: . Updated: .
SI is learning to move ancient banking programs to modern languages, but without human reviewers it is not yet trusted.
The facts below are from Engadget's account. OpenAI built the MultiLangBench set, where a model must write an SQLite-compatible database engine in a given language; GPT-6 Astra passed 87.4% of tests on average across 20 languages (GPT-5.6 Sol, 26.8%), with COBOL the hardest at 72%. When migrating programs from COBOL to C++, Java, Kotlin, Python or Rust while preserving behavior, GPT-6.1 Sol showed 97.9% accuracy at high reasoning effort and 86.6% at low. According to OpenAI, a migration counts as successful only if all tests pass, and production systems need expert review. Engadget cites OpenAI's estimate that about 40% of the world's banks still use COBOL.
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