From Prompting to Porting: Surviving the LLM Upgrade Cycle
TL;DR for operators A model upgrade is not a software patch. It is closer to changing the interpreter under a production system while hoping every old script still means the same thing. Charming, in the way live wires are charming. The paper behind this article, Prompt Migration: Stabilizing GenAI Applications with Evolving Large Language Models, studies that problem through Tursio, an enterprise search application that converts natural-language questions into structured operator trees for database querying.1 Tursio’s old prompts were fully stable on GPT-4-32k. When the same prompts were run against GPT-4.1, tests passed at 98%. Against GPT-4.5-preview, they passed at 97.3%. That sounds minor until the application is generating SQL-like structures, where “almost correct” is not a governance model. ...