Several changes were applied to improve security. See ADV-2017-11 through ADV-2017-15 in Security Bulletins for more details.
Published extracts based on Custom SQL could not be refreshed using the Data Extract Command Line Utility or the Online Sync Client (Tableau Bridge).
After upgrading to Tableau Server 10.2 or higher from a previous version, some views began timing out when you tried to load them.
Tabcmd export would fail if the URL to the view contained a dollar sign ($).
When embedded credentials was disabled, non-admin publishers trying to save a workbook in web authoring would encounter an unexpected error.
When you refreshed data in a view using the toolbar button, performance when reloading the view would sometimes be very slow.
If a workbook contained a Multiple Values (Custom List) filter, and was published with Prompt User authentication, an error would occur when the workbook was viewed in Tableau Server.
Published data sources containing custom SQL with parameters joined to other tables would fail to load with an error: Custom SQL relation refers to a non-existent parameter
Previously, turning off the Data Server global protocol pool (native_api.dataserver_single_protocol_pool) would also turn off the global query cache as a side-effect. Now, global query cache is controlled by a separate setting: native_api.dataserver_single_query_cache_service.
When your Tableau Server language was set to a European language, or Japanese, it was not possible to add a user permissions rule to a published data source.
When you enabled external SSL using a certificate key passphrase, the gateway process would sometimes fail to start.
In workbooks containing a live file-based connection using a UNC path, and an extracted cross-database join connection that also included a UNC path based connection, refreshing the workbook extract would cause the standalone live file-based connection to fail to update.
In some cases when you used a fixed axis, not all marks would be displayed after publishing the workbook to Tableau Server.
In some cases old extracts were not correctly cleaned up, potentially resulting in low disk space issues.