IBM Some portal resources have been updated, however a long cache was set so the updates are not being served. - United States  TECHNOTE (FAQ)

QUESTION
The resolver uses the digest to cache some URLs like resource aggregator collections, and the digest remains the same between restarts. Resources like theme files are served from the browser or proxy cache (HTTP 304) and not loaded from the server.


ANSWER
The resolver uses the digest to cache some URLs like resource aggregator collections, and the digest remains the same between restarts. 
In order to force a digest change (should some resources have changed and a long cache was set), you can set the "digest.seed" key in the WP ConfigService to any string value, which will be used in generating a new digest on server boot. This will force a digest change when you want a new one during a restart. 

Changing the digest setting generates different URLs, so the updated theme resources can be loaded from the server.
Why Theme Updates are not updated in the browser cache ? 

If you change graphics in page header. Then packed the war file and update it via the Integrated Solutions Console. But the old graphic is still displayed until the user press Ctrl + F5 in Internet Explorer.
Changing the digest setting generates different URLs, so the updated theme resources can be loaded from the server.