private static function file_set_version($package, \Datetime $version) {
		self::get_version($package);

		if (file_exists(Config::$migration_directory . '/db_version')) {
			$version_file = trim(file_get_contents(Config::$migration_directory . '/db_version'));
			$versions = json_decode($version_file, true);
		} else {
			$versions = [];
		}

		$versions[$package] = $version->format('Ymd His');
		file_put_contents(Config::$migration_directory . '/db_version', json_encode($versions));
	}