React DevTools v4 blog post (#2199)

Author: Brian Vaughn

content/blog/2019-08-15-new-react-devtools.md

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+---
+title: "Introducing the New React DevTools"
+author: [bvaughn]
+---
+We are excited to announce a new release of the React Developer Tools, available today in Chrome, Firefox, and (Chromium) Edge!
+
+## What's changed?
+
+A lot has changed in version 4!
+At a high level, this new version should offer significant performance gains and an improved navigation experience.
+It also offers full support for React Hooks, including inspecting nested objects.
+
+![DevTools version 4 screenshot](../images/blog/devtools-v4-screenshot.png)
+
+[Visit the interactive tutorial](https://react-devtools-tutorial.now.sh/) to try out the new version or [see the changelog](https://github.com/facebook/react/blob/master/packages/react-devtools/CHANGELOG.md#400-august-15-2019) for demo videos and more details.
+
+## Which versions of React are supported?
+
+**`react-dom`**
+
+* `0`-`14.x`: Not supported
+* `15.x`: Supported (except for the new component filters feature)
+* `16.x`: Supported
+
+**`react-native`**
+* `0`-`0.61`: Not supported
+* `0.62`: Supported
+
+## How do I get the new DevTools?
+
+React DevTools is available as an extension for [Chrome](https://chrome.google.com/webstore/detail/react-developer-tools/fmkadmapgofadopljbjfkapdkoienihi?hl=en) and [Firefox](https://addons.mozilla.org/en-US/firefox/addon/react-devtools/).
+If you have already installed the extension, it should update automatically within the next couple of hours.
+
+If you use the standalone shell (e.g. in React Native or Safari), you can install the new version [from NPM](https://www.npmjs.com/package/react-devtools):
+
+```shell
+npm install -g react-devtools@^4
+```
+
+## Where did all of the DOM elements go?
+
+The new DevTools provides a way to filter components from the tree to make it easier to navigate deeply nested hierarchies.
+Host nodes (e.g. HTML `<div>`, React Native `<View>`) are *hidden by default*, but this filter can be disabled:
+
+![DevTools component filters](../images/blog/devtools-component-filters.gif)
+
+## How do I get the old version back?
+
+If you are working with React Native version 60 (or older) you can install the previous release of DevTools from NPM:
+
+```shell
+npm install --dev react-devtools@^3
+```
+
+For older versions of React DOM (v0.14 or earlier) you will need to build the extension from source:
+
+```shell
+# Checkout the extension source
+git clone https://github.com/facebook/react-devtools
+
+cd react-devtools
+
+# Install dependencies and build the unpacked extension
+yarn install
+yarn build:extension
+
+# Follow the on-screen instructions to complete installation
+```
+
+## Thank you!
+
+We'd like to thank everyone who tested the early release of DevTools version 4.
+Your feedback helped improve this initial release significantly.
+
+We still have many exciting features planned and feedback is always welcome!
+Please feel free to open a [GitHub issue](https://github.com/facebook/react/issues/new?labels=Component:%20Developer%20Tools) or tag [@reactjs on Twitter](https://twitter.com/reactjs).