The latest release of Magento Open Source includes important security enhancements along with performance and functionality improvements. With these important updates we strongly recommend that you upgrade to ensure your sites maintain the highest level of security. You can review the release notes for more information about all of the enhancements. For more information about security updates included in these versions of Magento please see our Security Center: https://magento.com/security/patches/magento-2.2.6-and-2.1.15-security-update