This plugin is essentially unmaintained. If you have it installed and configured, it will probably keep on working for a while.
You might want to take a look at a similar plugin WP-ShredderChess.
This plugin uses the Yahoo YUI framework and an apparently unmaintained puzzle widget (last update in 2015).
It pulls in 600 KiB of JavaScript code, which is just a bit too much for such a simple widget.
Widget that displays the chess puzzle from
chesstempo.com.
Compatibility
This plugin is compatible with
ClassicPress.