The update comes just two weeks after the release of WordPress Version 4.5, which according to the blog post has already been downloaded roughly six million times.
The release addresses 12 bugs found in WordPress Version 4.5, including a singular class issue that breaks the Twenty Eleven theme and an Imagick bug that could break media uploads. It also fixes compatibility issues between specific versions of Chrome and the visual editor. A detailed list of changes can be viewed here.
If your site supports automatic background updates, then just sit back and relax, 4.5.1 is already being pushed out. If you’d rather not wait or have auto updates disabled, you can browse to Dashboard > Updates and click the Update Now button. If you encounter an issue or believe you’ve discovered a bug, please post it in the troubleshooting section of the support forums.