A new version of Calypso WordPress Theme, v2.3.3 has been released on March 10, 2016.
Theme Update Guide
You should receive an alert in your WordPress dashboard, simply click the Update button and the steps will be processed automatically . If you want to update the theme manually, download the latest version and replace “calypso” folder via a FTP.
Remember to always backup your website before any updates, not just this one.