diff --git a/src/Package_Command.php b/src/Package_Command.php
index <HASH>..<HASH> 100644
--- a/src/Package_Command.php
+++ b/src/Package_Command.php
@@ -137,6 +137,9 @@ class Package_Command extends WP_CLI_Command {
 	 *       version: dev-master
 	 */
 	public function browse( $_, $assoc_args ) {
+		if ( empty( $assoc_args['format'] ) || 'table' === $assoc_args['format'] ) {
+			WP_CLI::line( WP_CLI::colorize( '%CAlthough the package index will remain in place for backward compatibility reasons, it has been deprecated and will not be updated further. Please refer to https://github.com/wp-cli/ideas/issues/51 to read about its potential replacement.%n' ) );
+		}
 		$this->show_packages( 'browse', $this->get_community_packages(), $assoc_args );
 	}
Only display the notice when we can be sure a machine isn't using output