Open C:\Tomcat\webapps\WebOffice\metroUI\portal_config.js and configure for the parameter rssURL a valid URL for a RSS feed.

Configuration in portal_config.js
After that configuration, the landing page shows an additional, dynamic tile in the first place. In this tile all the news of the rss feed will be presented (in a loop). If you pick one of these news, the link to the news itself opens in the same browser tab.

News ticker in WebOffice html client
Note: WebOffice 10.5 SP2 supports only one tile for a news ticker.