# Modernizing complex legacy code with AI agents.

Publisher-attributed story with a reviewed brief or permitted publisher paragraph. The original publisher is responsible for the linked reporting.

- Publisher: Mistral AI
- Category: AI
- Original publication time: 2026-09-09T12:00:46Z
- First observed by NexusTechWire: 2026-10-01T20:28:42Z
- Original source: https://mistral.ai/news/legacy-code-modernization/
- NexusTechWire record: https://nexustechwire.com/news/news-42e9c4faaddaceedd5cd

## The brief

Mistral reports using AI agents to migrate 40,000 lines of a European energy operator's Fortran reservoir simulator into C++. The work combined numerical comparison tests, reconstructed documentation and human review of agent-generated changes. Mistral says fully autonomous attempts produced weaker results. The case study covers an initial portion of a 300,000-line system and cautions that projects without a working original program could be harder.

AI-assisted NexusTechWire summary, checked against the linked source on 2026-10-02T00:18:38Z. Not independent reporting.

Read the full original: [Mistral AI](https://mistral.ai/news/legacy-code-modernization/)

This record does not reproduce the complete article or represent independent confirmation of every source claim.