Drupal 8.3.x was released on April 5th 2017 and made several improvements to the caching system with the office stable release of BigPipe. It also added a new set of experimental modules which included Workflows, Layout Discovery and Field Layout. These are big steps forward in the Drupal 8 community because they lay the groundwork for integrating the best of Panels/Panelizer into core as “Layouts”.
This release also came with a large number of other minor updates and improvements ranging from content authoring and site builder improvements to enhanced security and performance. For a full list of updates released with the 8.3.x branch, check out the official release page here: https://www.drupal.org/project/drupal/releases/8.3.0.
Check out our posts on other Drupal 8 Core Updates to give you an overview of the updates that are to come.