We call it the .
It’s a beautiful theory. In practice, it often fails.
And that is exactly where it belongs. Share the oldest production code you’ve ever had to debug in the comments. 👇
Build the wall around the legacy. Starve it of new features. Feed the data to modern services. Eventually, you won't have a legacy core. You’ll have a legacy archive .
Why? Because the Legacy Core fights back. Every time you try to strangle a legacy function, you discover that function is coupled to a payroll system, which is coupled to a tax module, which requires a nightly batch job written in Perl.
Every business has one. That one system that nobody wants to touch. The codebase that has no tests, three layers of deprecated frameworks, and a single, terrified contractor in Nebraska who holds the encryption keys in their head.
You don’t need a rewrite. You need a siege.