Several changes were applied to improve security. See ADV-2017-17, ADV-2017-19, ADV-2017-20 and ADV-2017-21 in Security Bulletins for more details.
With recent updates to the Amazon Redshift driver, connections could fail with a no pg_hba.conf entry for host error. A workaround was to republish workbooks or data sources with Require SSL checked in the data connection.
Session Ended by Server errors would frequently occur when lazy connections were disabled.
When you published a statistical file to Tableau Server as a data source, Name unavailable would be displayed in the Connects To column in the Data Sources view on Tableau Server. Republishing the data source is required to correct the problem.
Workbooks loaded using URL parameters would error or fail to respect the URL parameters if the workbook was set to prompt for data source credentials.