function llms_backup_log( $handle ) {

	$file = llms_get_log_path( $handle );
	$size = file_exists( $file ) ? filesize( $file ) : 0;

	/**
	 * Filter the max filesize of a log file before the log is backed up
	 *
	 * The value of this filter, `$maxsize` is an integer representing the maximum number of megabytes
	 * a file can be before it is split.
	 *
	 * @since 4.5.0
	 *
	 * @param int $maxsize Maximum file size (in MB). The default value is `5` (5MB).
	 */
	$maxsize = absint( apply_filters( 'llms_log_max_filesize', 5 ) ) * 1000 * 1000;

	if ( $size >= $maxsize ) {

		$copy = str_replace( '.log', sprintf( '-%d.log.bk', time() ), $file );

		/**
		 * Filter the name of a log file copy that's being backed up because it's reached the maximum allowed size
		 *
		 * While it is possible to change the extension of the log file (`.log.bk`), it is not recommended. The cron
		 * which creates copies filters out `.log.bk` so that it doesn't scan backups and attempt to split them
		 * again (infinitely).
		 *
		 * @since 4.5.0
		 *
		 * @param string $copy   Full path for the copy log file (the backup).
		 * @param string $file   Full path for the original log file.
		 * @param string $handle Log file handle.
		 */
		$copy = apply_filters( 'llms_log_split_file_name', $copy, $file, $handle );
		if ( rename( $file, $copy ) ) {

			/**
			 * Action triggered immediately following the creation of a logfile backup.
			 *
			 * @since 4.5.0
			 *
			 * @param string $copy   Full path for the copy log file (the backup).
			 * @param string $file   Full path for the original log file.
			 * @param string $handle Log file handle.
			 */
			do_action( 'llms_log_file_backup_created', $copy, $file, $handle );

			return $copy;
		}
	}

	return null;

}