Why are the antivirus definitions and the stargate version so old after I upgrade Symantec Protection Engine (SPE)?
When Symantec Protection Engine (SPE) is upgraded it can be configured to preserve all settings or perform a clean upgrade. When it is in the upgrade process it will revert to the base engine and definitions of the previous SPE version. The reason it does this is that there may be a compatibility issue during the upgrade process.
Recently upgraded SPE environment.
This is expected behavior. The stargate version and the antivirus definition version should update again as soon as liveupdate runs. When you install or upgrade Symantec Protection Engine, LiveUpdate is enabled by default to run every two hours.
Additional information on LiveUpdate can be found in the technical documentation for Symantec Protection Engine. Select the appropriate version and in the "Search this product" field search for LiveUpdate.