WordPress 4.8.1 is a maintenance release that addresses 29 bug fixes and enhancements.
Things to note
Among the fixes/enhancements are updates to the rich Text widget and the introduction of the Custom HTML widget. You can read more by looking at the release notes: https://codex.wordpress.org/Version_4.8.1
If you have not done so already – download the update or simply use your existing installation of WordPress to update your site. Either way – this is an excellent time to make a backup copy of your site(s) before upgrading.