Versioning Policy

This versioning policy describes our approach to version numbers for packages such as react and react-dom. For a list of previous releases, see the Versions page.

Stable releases

Stable React releases (also known as “Latest” release channel) follow semantic versioning (semver) principles.

That means that with a version number x.y.z:

• When releasing critical bug fixes, we make a patch release by changing the z number (ex: 15.6.2 to 15.6.3).
• When releasing new features or non-critical fixes, we make a minor release by changing the y number (ex: 15.6.2 to 15.7.0).
• When releasing breaking changes, we make a major release by changing the x number (ex: 15.6.2 to 16.0.0).

Major releases can also contain new features, and any release can include bug fixes.

Minor releases are the most common type of release.

We know our users continue to use old versions of React in production. If we learn of a security vulnerability in React, we release a backported fix for all major versions that are affected by the vulnerability.

Breaking changes

Breaking changes are inconvenient for everyone, so we try to minimize the number of major releases – for example, React 15 was released in April 2016 and React 16 was released in September 2017, and React 17 was released in October 2020.

Instead, we release new features in minor versions. That means that minor releases are often more interesting and compelling than majors, despite their unassuming name.

Commitment to stability

As we change React over time, we try to minimize the effort required to take advantage of new features. When possible, we’ll keep an older API working, even if that means putting it in a separate package. For example, mixins have been discouraged for years but they’re supported to this day via create-react-class and many codebases continue to use them in stable, legacy code.

Over a million developers use React, collectively maintaining millions of components. The Facebook codebase alone has over 50,000 React components. That means we need to make it as easy as possible to upgrade to new versions of React; if we make large changes without a migration path, people will be stuck on old versions. We test these upgrade paths on Facebook itself – if our team of less than 10 people can update 50,000+ components alone, we hope the upgrade will be manageable for anyone using React. In many cases, we write automated scripts to upgrade component syntax, which we then include in the open-source release for everyone to use.

Gradual upgrades via warnings

Development builds of React include many helpful warnings. Whenever possible, we add warnings in preparation for future breaking changes. That way, if your app has no warnings on the latest release, it will be compatible with the next major release. This allows you to upgrade your apps one component at a time.

Development warnings won’t affect the runtime behavior of your app. That way, you can feel confident that your app will behave the same way between the development and production builds — the only differences are that the production build won’t log the warnings and that it is more efficient. (If you ever notice otherwise, please file an issue.)

What counts as a breaking change?

In general, we don’t bump the major version number for changes to:

• Development warnings. Since these don’t affect production behavior, we may add new warnings or modify existing warnings in between major versions. In fact, this is what allows us to reliably warn about upcoming breaking changes.
• APIs starting with unstable_. These are provided as experimental features whose APIs we are not yet confident in. By releasing these with an unstable_ prefix, we can iterate faster and get to a stable API sooner.
• Alpha and Canary versions of React. We provide alpha versions of React as a way to test new features early, but we need the flexibility to make changes based on what we learn in the alpha period. If you use these versions, note that APIs may change before the stable release.
• Undocumented APIs and internal data structures. If you access internal property names like __SECRET_INTERNALS_DO_NOT_USE_OR_YOU_WILL_BE_FIRED or __reactInternalInstance$uk43rzhitjg, there is no warranty. You are on your own.

This policy is designed to be pragmatic: certainly, we don’t want to cause headaches for you. If we bumped the major version for all of these changes, we would end up releasing more major versions and ultimately causing more versioning pain for the community. It would also mean that we can’t make progress in improving React as fast as we’d like.

That said, if we expect that a change on this list will cause broad problems in the community, we will still do our best to provide a gradual migration path.

If a minor release includes no new features, why isn’t it a patch?

It’s possible that a minor release will not include new features. This is allowed by semver, which states “[a minor version] MAY be incremented if substantial new functionality or improvements are introduced within the private code. It MAY include patch level changes.”

However, it does raise the question of why these releases aren’t versioned as patches instead.

The answer is that any change to React (or other software) carries some risk of breaking in unexpected ways. Imagine a scenario where a patch release that fixes one bug accidentally introduces a different bug. This would not only be disruptive to developers, but also harm their confidence in future patch releases. It’s especially regrettable if the original fix is for a bug that is rarely encountered in practice.

We have a pretty good track record for keeping React releases free of bugs, but patch releases have an even higher bar for reliability because most developers assume they can be adopted without adverse consequences.

For these reasons, we reserve patch releases only for the most critical bugs and security vulnerabilities.

If a release includes non-essential changes — such as internal refactors, changes to implementation details, performance improvements, or minor bugfixes — we will bump the minor version even when there are no new features.

All release channels

React relies on a thriving open source community to file bug reports, open pull requests, and submit RFCs. To encourage feedback we sometimes share special builds of React that include unreleased features.

Each of React’s release channels is designed for a distinct use case:

• Latest is for stable, semver React releases. It’s what you get when you install React from npm. This is the channel you’re already using today. User-facing applications that consume React directly use this channel.
• Canary tracks the main branch of the React source code repository. Think of these as release candidates for the next semver release. Frameworks or other curated setups may choose to use this channel with a pinned version of React. You can also use Canaries for integration testing between React and third party projects.
• Experimental includes experimental APIs and features that aren’t available in the stable releases. These also track the main branch, but with additional feature flags turned on. Use this to try out upcoming features before they are released.

All releases are published to npm, but only Latest uses semantic versioning. Prereleases (those in the Canary and Experimental channels) have versions generated from a hash of their contents and the commit date, e.g. 18.3.0-canary-388686f29-20230503 for Canary and 0.0.0-experimental-388686f29-20230503 for Experimental.

Both Latest and Canary channels are officially supported for user-facing applications, but with different expectations:

• Latest releases follow the traditional semver model.
• Canary releases must be pinned and may include breaking changes. They exist for curated setups (like frameworks) that want to gradually release new React features and bugfixes on their own release schedule.

The Experimental releases are provided for testing purposes only, and we provide no guarantees that behavior won’t change between releases. They do not follow the semver protocol that we use for releases from Latest.

By publishing prereleases to the same registry that we use for stable releases, we are able to take advantage of the many tools that support the npm workflow, like unpkg and CodeSandbox.

Latest channel

Latest is the channel used for stable React releases. It corresponds to the latest tag on npm. It is the recommended channel for all React apps that are shipped to real users.

If you’re not sure which channel you should use, it’s Latest. If you’re using React directly, this is what you’re already using. You can expect updates to Latest to be extremely stable. Versions follow the semantic versioning scheme, as described earlier.</