How does Agile solve the problem when a requirement arrives in the last sprints, for which you have to redo everything?

Question

Agile

Hello!

An explanation is required from comrades experienced in Agile:
How does Agile solve a problem when, at the later stages of development, in the last sprints, a requirement suddenly appears, the implementation of which will require improvements that are critical in terms of complexity and duration? Simply put, the entire architecture of the solution turns out to be unsuitable for this requirement and it turns out that everything will have to be redone. After all, the architecture was built only on the basis of previous requirements.

Are there techniques in Agile that will help prevent such situations?

Answer 1

No, no methodology protects against this.
But you can slightly reduce the risks if, at earlier stages, you lay down an architecture that can be easily expanded / changed.

Answer 2

For some reason I don't think so . This is the essence of agile - not to think about global problems that seem to be non-existent today. It seems to sound right. But it is always necessary to think more about architecture than is required by today's requirements. But. This is low.
My advice - the requirement in the firebox. Although, if you think about it ;). But after all, without him, too, there will be nothing. Well, then n-number of people from under agile are displayed and they re-release the new architecture in a new branch. This, of course, is still a rake and coordinating both branches is not much fun. Alas, I don't have a recipe.
Because you can not wash and not get wet. And that's all they want.