diff --git a/docs/faq.md b/docs/faq.md
index 83cb2d0541..e329ffe0de 100644
--- a/docs/faq.md
+++ b/docs/faq.md
@@ -526,6 +526,7 @@ If the registry returns `401 Unauthorized` or `"code":"UNAUTHORIZED"`, it is oft
 
 * You did not configure auth information in the default places where Jib searches.
    - `$HOME/.docker/config.json`, [one of the configuration files](https://docs.docker.com/engine/reference/commandline/cli/#configuration-files) for the `docker` command line tool. See [configuration files document](https://docs.docker.com/engine/reference/commandline/cli/#configuration-files), [credential store](https://docs.docker.com/engine/reference/commandline/login/#credentials-store) and [credential helper](https://docs.docker.com/engine/reference/commandline/login/#credential-helpers) sections, and [this](https://github.com/GoogleContainerTools/jib/issues/101) for how to configure auth. For example, you can do `docker login` to save auth in `config.json`, but it is often recommended to configure a credential helper (also configurable in `config.json`).
+   - (Starting from Jib 2.2.0) You can set the environment variable `$DOCKER_CONFIG` for the _directory_ containing Docker configuration files. `$DOCKER_CONFIG/config.json` takes precedence over `$HOME/.docker/config.json`.
    - Some common credential helpers on `$PATH` (for example, `docker-credential-osxkeychain`, `docker-credential-ecr-login`, etc.) for well-known registries.
    - Jib configurations
       - Configuring credential helpers: [`<from/to><credHelper>`](https://github.com/GoogleContainerTools/jib/tree/master/jib-maven-plugin#using-docker-credential-helpers) (Maven) / [`from/to.credHelper`](https://github.com/GoogleContainerTools/jib/tree/master/jib-gradle-plugin#using-docker-credential-helpers) (Gradle)