cache_format

Name: Caching Format to Use Type: Number Default: 0 Available In: Revolution 2.1+

Values:

• 0: PHP arrays
• 1: JSON
• 2: PHP serialized data

IMPORTANT: Do not change this value in System Settings. If you edit it in the manager, MODX writes cache in the new format while old-format files still sit on disk. The site and the manager can then fail to boot.

To override the default, set it in $config_options in core/config/config.inc.php, then empty the core/cache/ directory:

$config_options = [
    'cache_format' => 0, // 0 = PHP, 1 = JSON, 2 = serialize
];

See also: Using Memcache for another $config_options example.