Several changes were applied to improve security. See ADV-2017-016 & ADV-2017-018 in Security Bulletins for more details.
A session ended by server error would occur when loading certain workbooks.
Published live connection data sources, containing a larger number of joined tables, could often perform very slowly with noticeable delays after every action taken in Tableau Desktop.
The Get Users on Site REST API call would sometimes return duplicate values.
Auto-complete for calculated fields did not work in web authoring when copying and pasting text into the calculation dialog.
Backgrounder processes would sometime crash during periodic process restarts. Crash dump files were generated during these periodic events and eventually resulted in excessive disk space consumption.
A typically benign error, Failed to load proxy credentials: 'The parameter is incorrect.' showed up excessively in log files, making troubleshooting difficult.
The Export to PDF dialog would be truncated when you rotated an iPad Mini to landscape orientation and attempted to export a view to PDF using an iOS compatible browser.
When you published a workbook to a project, and then the workbook was moved to a different project by a server administrator, attempting to publish a workbook with the same name to the original project would result in an error: Workbook name is already in use. Publishing will overwrite the existing workbook.
Activating or refreshing a license key for Tableau Server would fail with a maximum activations error more often than expected.