Upgrades and modernisation: 3 sourced coding agent stories
Version upgrades and bringing old code up to date. Of the 3 stories, 2 were published by a tool vendor and 1 by the people who did the work. 3 involve an existing codebase and 0 started from scratch. Every number links to where it was published.
- Practitioner (own blog/paper) Upgrade / modernisation brownfield
Claude Code ports a 25-year-old Linux tape driver from kernel 2.4 to 6.8 over two evenings
Dmitry Brant (independent developer) · 2025-09-07
- Two evenings Time
- 2.4 → 6.8 Kernel version jump
- Probably several weeks (would have meant learning 25-year-old kernel development) Author's by-hand estimate
Claude Code
- Vendor-published Upgrade / modernisation brownfield
Amazon upgrades tens of thousands of production apps to Java 17 with Amazon Q Developer
Amazon · 2024-08-01
- Tens of thousands (Java 8/11 → 17) Applications upgraded
- 4,500+ years Development work saved (estimate)
- $260M from performance improvements Annual cost savings (estimate)
Amazon Q Developer
- Vendor-published Upgrade / modernisation brownfield
Altisource modernizes 350,000 lines of legacy Java with Amazon Q Developer
Altisource
- 350,000+ lines Legacy Java modernized
- +25% (one modernization team, 'up to') Developer productivity
- ~160 → 200 Story points (3-month avg per engineer)
Amazon Q Developer