What's Changed

6.13.0 is really a patch release in spirit but comes with a SemVer minor bump since we added a new future flag.

The tl;dr; is that 6.13.0 is the same as 6.12.0 bue we've moved the usage of React.startTransition behind an opt-in future.v7_startTransition future flag because we found that there are applications in the wild that are currently using Suspense in ways that are incompatible with React.startTransition.

Therefore, in 6.13.0 the default behavior will no longer leverage React.startTransition:

<BrowserRouter>
  <Routes>{/*...*/}</Routes>
</BrowserRouter>

<RouterProvider router={router} />

If you wish to enable React.startTransition, pass the future flag to your router component:

<BrowserRouter future={{ v7_startTransition: true }}>
  <Routes>{/*...*/}</Routes>
</BrowserRouter>

<RouterProvider router={router} future={{ v7_startTransition: true }}/>

We recommend folks adopt this flag sooner rather than later to be better compatible with React concurrent mode, but if you run into issues you can continue without the use of React.startTransition until v7. Issues usually boil down to creating net-new promises during the render cycle, so if you run into issues when opting into React.startTransition, you should either lift your promise creation out of the render cycle or put it behind a useMemo.

Minor Changes

• Move React.startTransition usage behinds a future flag (#10596)

Patch Changes

• Work around webpack/terser React.startTransition minification bug in production mode (#10588)

Full Changelog: https://github.com/remix-run/react-router/compare/react-router@6.12.1...react-router@6.13.0