| --- |
| layout: documentation |
| title: Updating Bazel |
| category: getting-started |
| --- |
| |
| # Updating Bazel |
| |
| This page covers how to automatically update your Bazel version using Bazelisk. |
| |
| The Bazel project has a [backward compatibility |
| policy](https://docs.bazel.build/versions/main/backward-compatibility.html) |
| (see [guidance for rolling out incompatible |
| changes](https://www.bazel.build/maintaining/breaking-changes-guide.html) if you |
| are the author of one). That page summarizes best practices on how to test and |
| migrate your project with upcoming incompatible changes and how to provide |
| feedback to the incompatible change authors. |
| |
| ## Managing Bazel versions with Bazelisk |
| |
| [Bazelisk](https://github.com/bazelbuild/bazelisk) helps you manage Bazel |
| versions. |
| |
| Bazelisk can: |
| * Auto-update Bazel to the latest LTS or rolling release. |
| * Build the project with a Bazel version specified in the .bazelversion |
| file. Check in that file into your version control to ensure reproducibility |
| of your builds. |
| * Help migrate your project for incompatible changes (see above) |
| * Easily try release candidates |
| |
| ## Recommended migration process |
| |
| Within minor updates to any LTS release, any |
| project can be prepared for the next release without breaking |
| compatibility with the current release. However, there may be |
| backward-incompatible changes between major LTS versions. |
| |
| Follow this process to migrate from one major version to another: |
| |
| 1. Read the release notes to get advice on how to migrate to the next version. |
| 1. Major incompatible changes should have an associated `--incompatible_*` flag |
| and a corresponding GitHub issue: |
| * Migration guidance is available in the associated GitHub issue. |
| * Tooling is available for some of incompatible changes migration. For |
| example, [buildifier](https://github.com/bazelbuild/buildtools/releases). |
| * Report migration problems by commenting on the associated GitHub issue. |
| |
| After migration, you can continue to build your projects without worrying about |
| backward-compatibility until the next major release. |
