This is intended for Web Viewer 12.1 "FULL" installations that include Apache Tomcat. If you are using Apache Tomcat from another source, do not use this solution. You should obtain the Apache Tomcat update from that other source.
To access this update, download RO91790 UPDATE APACHE TOMCAT TO 8.5.4. For installation instructions for the solution provided which is provided as a ZIP file, refer to the SpecialInstructions.txt file included with the download.