Hi,
Thank you for reporting this. The UCP plugin was missing from the 6.4.0 package due to a packaging error. The plugin source files were included in the release but the packaging configuration didn't list them, so they were not copied into the final ZIP.
We have fixed this. Please download the updated 6.4.0 package from your member area and reinstall. After installation, you will find the UCP plugin in HikaShop's System > Plugins menu. It is disabled by default. Enable it and configure it following the documentation:
www.hikashop.com/support/documentation/5...mmerce-protocol.html