Drupal 8 is scheduled for release in late 2014. It will bring improvements like configuration management, REST services, responsive design, improved multilingual support, and more core modules. While most contributed modules have not yet been upgraded for Drupal 8, upgrading from Drupal 7 is not necessary due to feature parity and potential issues. Sites running Drupal 6 may benefit more from upgrading. The best time to upgrade is when restructuring or rebuilding a Drupal 7 site; this allows migrating content and configuration while adapting to a new structure.