They’ll fail. I worked on a successful rewrite of a 25 years old Perl codebase. We did it because we had a strong understanding of the business, of the existing

They’ll fail. I worked on a successful rewrite of a 25 years old Perl codebase. We did it because we had a strong understanding of the business, of the existing codebase, and were not afraid to maintain both in parallel. It took us years to migrate most of it blocks by blocks (some parts are still in Perl and likely won’t ever be migrated for various reasons) because a rewrite is not just converting some code, it’s an opportunity to rethink the whole architecture and responsibilities. Doing a rewrite is doable and might be suitable, but I guarantee no one there has any idea what they’re doing. They wouldn’t talk of "months" otherwise. 60 million lines is a 5-10 years rewrite, realistically.