The CDB specification evolution is now done via OGC. The Standard working Group (SWG) is open to suggestions.
You can use the change request mechanism as a non-OGC member or join OGC and participate actively to CDB and other standards development.
The CDB user group held at I/ITSEC every year is no longer since the transition to OGC. However, a "CDB user information exchange session" has been hosted by US-SOCOM at I/ITSEC 2016 to share some of the recent CDB tools developments.
All CDB specification change request must be submitted to OGC from now on.
When and where are the CDB group meeting to discuss new features proposed in future CDB spec.