diff --git a/jib-gradle-plugin/README.md b/jib-gradle-plugin/README.md
index 7ae6237045..aa76e49d39 100644
--- a/jib-gradle-plugin/README.md
+++ b/jib-gradle-plugin/README.md
@@ -254,7 +254,7 @@ Property | Type | Default | Description
 `extraClasspath` | `List<String>` | *None* | Additional paths in the container to prepend to the computed Java classpath.
 `expandClasspathDependencies` | `boolean` | `false` | <ul><li>Java 8 *or* Jib < 3.1: When set to true, does not use a wildcard (for example, `/app/lib/*`) for dependency JARs in the default Java runtime classpath but instead enumerates the JARs. Has the effect of preserving the classpath loading order as defined by the Gradle project.</li><li>Java >= 9 *and* Jib >= 3.1: The option has no effect. Jib *always* enumerates the dependency JARs. This is achieved by [creating and using an argument file](#custom-container-entrypoint) for the `--class-path` JVM argument.</li></ul>
 `filesModificationTime` | `String` | `EPOCH_PLUS_SECOND` | Sets the modification time (last modified time) of files in the image put by Jib. (Note that this does not set the image creation time, which can be set using `jib.container.creationTime`.) The value should either be `EPOCH_PLUS_SECOND` to set the timestamps to Epoch + 1 second (default behavior), or an ISO 8601 date-time parsable with [`DateTimeFormatter.ISO_DATE_TIME`](https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/time/format/DateTimeFormatter.html#ISO_DATE_TIME) such as `2019-07-15T10:15:30+09:00` or `2011-12-03T22:42:05Z`. The value can also be initialized [lazily](https://docs.gradle.org/current/userguide/lazy_configuration.html) with a provider.
-`format` | `String` | `Docker` | Use `OCI` to build an [OCI container image](https://www.opencontainers.org/).
+`format` | `ImageFormat` | `ImageFormat.Docker` | Use `ImageFormat.OCI` to build an [OCI container image](https://www.opencontainers.org/).
 `jvmFlags` | `List<String>` | *None* | Additional flags to pass into the JVM when running your application. The value can also be initialized [lazily](https://docs.gradle.org/current/userguide/lazy_configuration.html) with a provider.
 `labels` | `Map<String, String>` | *None* | Key-value pairs for applying image metadata (similar to Docker's [LABEL](https://docs.docker.com/engine/reference/builder/#label) instruction).
 `mainClass` | `String` | *Inferred*\*\* | The main class to launch your application from. The value can also be initialized [lazily](https://docs.gradle.org/current/userguide/lazy_configuration.html) with a provider.