Another release so soon? Yep. Unfortunately, the most recent version of the THREDDS Data Server, v4.6.9 (released 2017-04-17), shipped with a major bug that prevented a fresh installation of TDS from starting, and that bug has been fixed in this release. It also addresses an issue with the 'NetCDF-Java ToolsUI (webstart)' viewer failing to start.
For more information, including bug fixes and download links, please see the full announcement on the Unidata THREDDS GitHub release page.