CentOS 5.11 packages have been removed from CentOS mirrors due to the EOL of the operating system. To successfully perform software update on a UCX 4.0 system to the latest software version, perform the following steps:
1. From the UCX Web-based Configuration Utility, navigate to the System – Updates – Repositories page
2. Uncheck all the CentOS-5 repositories.
3. Press the Save/Update button to save the changes
4. Navigate to the System – Updates – Software Update page and perform a software update to the system as per normal.