This is a companion discussion topic for the original entry at https://www.rstudio.com/blog/shiny-server-pro-1-5-4
Shiny Server 1.5.4.869 and Shiny Server Pro 1.5.4.872 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 1.5.4.869 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.