Before version 5.5, CQ was built on a servlet container (CQSE by default, but others may be used) that ran multiple web applications: one for the CRX content REPOSITORY and ANOTHER for the OSGi container, which contained Sling and AEM. The majority of the request processing was handled by the Sling web app, which was connected to the root. The following are some POINTS to remember for CQ5.5:

• The OSGi container is at the root of CQ 5.5 and AEM, with the OSGi HTTP service, supported by Sling, acting as the only request handling endpoint.
• Along with the many services that make up the rest of the AEM functionality, the CRX content repository is now just another OSGi service. These modifications have no impact on AEM or Sling-based apps.
• Because of the new design, AEM's quickstart jar installation can no longer enable the use of other web applications alongside AEM.
• The war version of AEM, on the other hand, is designed to be installed in an application server alongside other web applications.
• Three new connectors for Adobe products – Creative Suite, Scene7, and Search&Promote – have been added.
• The AUTHORS will be able to work directly on mobile applications.
• Hybrid software was partnered with to GIVE some wonderful eCommerce functionality.
• Undo(Ctrl+z) and Redo(Ctrl+y) functions have been added.