Support said that it should upgrade. If the client is at 9.3.x and you run a client task to install 10 it should upgrade. Probably will need a reboot as well.
The DLPe 10 Client is an upgrade to the DLPe 9.3 Client.
But, the Incident Management, Classification Configuration, and Policy Configuration and Management is a completely new and different product starting with 9.4.
Best to treat them as separate products.
Manage 9.3 and older agents and rules with the 9.3 tools, and manage the 10.0 and newer agents and rules with the 10.0 tools.
The 9.4/10.0 and later Classification and Policy Management tools have so many new capabilities, and approach building the rules in such new ways I found it best to build everything in 10.0 from scratch.
We did not have good luck with the 9.3 to 9.4/10.0 policy conversion server task. Either things didn't come over correctly, or it didn't take advantage of new capabilities with the 9.4/10.0 product.
Thanks for the notes! In testing, I found that installing 10 over 9.3 works fine, a reboot IS REQUIRED for the product to work properly. Duly noted on the rules migration, in this case, they only had DCM rules, so rebuilding them from scratch was easy.