Your new software shouldn't do everything your old software does.

“The new X must do exactly what the old X does.”
-- Your Product Manager

Over the past 2 decades, I've been assigned projects like this. Have you ever seen it? I call it requirements laziness. It's trying to offload product definition onto developers.

Ian Cartwright and Rob Horn have a similar concept: feature parity.

🧵👇#softwareengineering #whyrewrite #featureparity #requirementlaziness