The current version of the plugin 1.7.17 has been tested up to WordPress 4.4.1 but the code is not dependent on any breaking changes inserted by the WordPress core developers in the newer releases. Unless WordPress introduces really big breaking changes the plugin will keep working with every minor updates at 4.x.x.
However, if you really want to make sure that the plugin will work with the WordPress you have installed, I encourage you to use the development version of the code [1] which is always tested against the latest version of WordPress available, now at 4.5.3. It has significant improvements that will be released soon once the QA process is finished [2].
[1] https://github.com/cixtor/sucuri-wordpress-plugin/archive/master.zip
[2] https://github.com/Sucuri/sucuri-wordpress-plugin
