This is a minor update.
Following the practice begun at plugin version 1.1.2 of having the plugin version number match the version number of the bundled copy of Pym.js, the first three numbers in this plugin's version do not change with this release because the Pym.js version has not changed. We've increased the fourth digit of the version number from .3 to .4 to denote this release. Please read the release notes and test your site as appropriate before upgrading in production.
You can download the plugin here, or through the WordPress.org plugin repository.