Shiny Server (Pro) 1.5.4

This is a companion discussion topic for the original entry at

Shiny Server and Shiny Server Pro are now available.
Both the new Shiny Server and Shiny Server Pro releases include bug fixes and enhancements, and we recommend upgrading at your earliest convenience.
Shiny Server Clickjacking protection can now be enabled using the frame_options directive. This directive was already available in Shiny Server Pro, but is now available in Shiny Server as well. A bug that caused "Error: Can't set headers after they are sent.