A new version of the best-in-class Magento Page Cache has been released today. This is our 32nd version of the Full Page Cache and it includes two important new features.
Information Sharing – In previous versions of the page cache the primary and secondary cache were essentially in their own walled garden. The consequence of this meant that unless you had a very busy site the secondary cache was not very useful because it would never be warmed (90%+ of requests are served by the faster primary cache). Now, the primary and secondary cache share information, so as items are added to the primary cache they will also be usable to the secondary cache if applicable. The end result of this is a much higher cache rate for the secondary cache.
Footer Widget – The footer widget is an informational feature for power users that want to see which cache level is being used to serve a request. In previous versions you could use an HTTP header viewer to view this information, but many store owners found this to be complicated. The footer widget is a good alternative to using an HTTP header viewer. It will add a black bar at the very bottom of your site that tells such information as cache level, time to live, and the cache key.