First check that the update site is configured. From the Eclipse IDE:
Window > Preferences > Install/Update > Available Software Sites
If you don't have the entry for "Elastic COBOL Updates", click Add and fill in the details as in the image above.
Now the update site is configured, from the Eclipse IDE you can check for updates by:
Help > Check for Updates
Once the update is installed, it is highly recommended that you rebuild all of your projects:
Project > Clean... > Clean all projects > OK