Instead of doing a Product Deployment task, you need to do a Product Upgrade task. The Agent allows you to upgrade through Product Deployment (because you can install a newer copy of the Agent over an older copy of the Agent), but VSE patches must be deployed through a Product Upgrade task.
First, you have to check in the VSE patch package. There are two packages; the full installer and the upgrade installer. The full installer will install the product through a Product Deployment task. The upgrade installer will upgrade a previous version of VSE 8.8 through a Product Upgrade task. Make sure the Patch 6 upgrade package is checked into ePO and pushed to any distributed repos you may have. I assume you'll have checked this into the Evaluation branch, but you can push the product through any branch.
Second, you must configure an Agent policy for the endpoints you wish to upgrade. The Updates tab of the Agent policy tells the Agent which branch it should check for upgrades to the VSE client (also for DAT files, engine upgrade, SAE upgrades, etc.). Change the Agent policy to look at the Evaluation branch for VSE upgrades. Assign this policy to the endpoints you want to upgrade and push it out through a wake-up call (or let it get pulled down through the normal ASCI).
Finally, you have to create a Product Upgrade task and execute it on the client. The upgrade task must look for VSE upgrades. Then execute that task against the client, and it'll upgrade.
Be careful where you check in the upgrade installer, especially if you're using Global Updating or already have a regular task configured that looks for VSE updates. I've definitely accidentally checked a patch into a branch and pushed it to a large number of endpoints without realizing it!
Sorry if that can't be more descriptive; I'm not in the office right now so all this is off the top of my head.
Thanks a lot for the detailed reply. I was able to upgrade VSE from patch 5 to patch 6 using the first option your method you mentioned. And as far as policies are concerned there's a General Agent policy which checks for VSE, DAT, and Engine etc updates. Being a default policy I left it as it is and didn't make any changes.
But you're right about being careful about checking in Upgrade (Patch 6) installer as it automatically pushed VSE patch 6 update on all machines present in ePO due to General Agent policy > Updates tab options. Though It didn't cause me any issues as there were only few test machines.
I appreciate for your help.
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