What’s the most painful legacy code migration you’ve dealt with?

Everyone talks about “legacy code,” but the pain looks different for each team.

For me, it’s usually:

• Framework upgrades breaking hidden assumptions

• JS → TypeScript migrations taking weeks

• Refactors that stall feature work

Curious what’s been hardest for you:

• Backend framework migrations?

• Frontend rewrites?

• Monolith → modular?

• Something else?

Would love to hear real war stories 👇