This is the quickest way to force Software Center to check for new applications and updates.  You will need to be on the DMU network or connected to VPN for this to work.

1. Open the Configuration Manager control panel on the computer.
   • Start button > start typing "control panel" > click Control Panel
   •  
2. Switch to the Actions tab. Select Machine Policy Retrieval & Evaluation Cycle to start the computer policy, and then select Run Now.
   • 
3. The selected cycle will run and might take several minutes to finish.
4. Select OK to confirm the prompt.
5. You should see any changes shortly in Software Center if there are new applications or updates available.
   • Overview: Software Center | Knowledge Base | Solutions Hub (freshservice.com)