Save ACF fields JSON after update

add_filter('acf/settings/save_json', 'aterm_acf_json_save_point');
function aterm_acf_json_save_point($path)
{
    // update path
    $path = get_stylesheet_directory() . '/acf-json';
    // return
    return $path;
}

Whenever you save or update an ACF field group, the field settings will be stored as a JSON file in the acf-json folder inside your theme directory. This allows for easier version control of ACF field settings and makes it simple to move fields between environments.