Yes, the feature set of version 5 was ready, before v4 was released so we are going straight to version 5. Version 5 includes call recording AND phone provisioning, both slated for v5. Some delay on V4 but V5 was here faster then expected.
V4.0 - ALPHA VERSION should be skipped. I think we no need to care the V4 or V5....... Just a version number only. The most important things is we want a powerful, reliable and stable IPPBX system.