eZ Publish is an Enterprise Open-Source Content Management System/Framework (CMS/F) at its core. It is highly extendable so with extensions it provides "WCMS" capabilities. Its default Enterprise offering as of version 5, "eZ Publish Platform", is extended to provide full set of Customer Experience Management (CXM) capabilities.
Version 5 represents a big step forward for eZ Publish, as it introduces a whole new architecture and embraces the full Symfony2 stack and community around it. As is often the case with architecture, most of it is under the hood in current releases, and there is no new User Interfaces (UI) yet running on the new kernel; however with our "Dual-kernel" approach all existing UI's are still here running on legacy kernel.
From high level 5.x kernel is:
For more information on the status eZ Publish 5.x, known issues, change logs and architecture updates, see the latests release notes.