[acemarke]

Nope. Redux does require that your reducers update their state immutably, but does not care HOW you do so. You can do it with Object.assign() / _.extend(), array slicing, the object spread operator, Immutable.js, the React Immutability Helpers, or one of the umpteen libs that provide abstractions for immutable updates like dot-prop-immutable or object-immutable-path.