The latest version of Herschel is 12.0034
You can check which version you're currently running by looking in the main Herschel window:
Once you've downloaded the upgrade, and when nobody is using Herschel, run the upgrade program Herschel_v12_Upgrade.exe and follow the straightforward on-screen instructions.
Windows may warn you about starting an unrecognised app. To continue with the upgrade, click here:
Then click here: