Agent updates should use the configured patch file source instead of pulling from the KServer directly.
Updating a client with a load of agents takes forever and slows the client's available bandwidth to a crawl. At 4 MB a pop, 500 agents is 2 gigabytes they need to download over the internet, when it should be set so the patch file source downloads it once and the clients can grab it off the LAN.
You can distribute the agent update files from a LAN server instead of the KServer by assigning a LAN Cache to the endpoint. Use the Agent > LAN Cache function to create a LAN Share on a server. Then use the Agent > Assign LAN Cache function to assign the above server to the endpoint. When the agent is updated, the files will distribute via the LAN Cache instead of the KServer (KServer will only be involved if the LAN Cache doesn't have the appropriate files, which will get updated on the LAN Cache for future distributions).
That's useful to know in the future, but unfortunately it doesn't help during this upgrade.
"LAN Cache cannot be assigned to machines with an agent version less than 126.96.36.199. Update agent to the latest version."
Indeed, this is the "from v6.2 w/ no LAN Cache to v6.3 w/ LAN Cache crossover" phase.
In fact, even if you were to update your desired LAN Cache host agent to v6.3 (to not encounter that display logic restriction) and then set it up as a LAN Cache host machine, the assigned v6.2-based agents still would not use LAN Cache for the agent update files as the agent LAN Cache assignment logic and code is done in the v6.3-based WIn Agent onwards only. Going forward, future versions of the agent upgrade would use it though (ie.: v6.3 to v6.4, etc...).
So, from here, in just this transition VSA version phase, if internet usage/bandwidth consumption is of most important and prominence here (regardless of distributing the updates in the agent update scheduler, since if done faster or slower w/ distribution the same bandwidth is consumed), you do of course have the option to download a /s (w/ creds) & /r-based package, store it locally on a share somewhere, and create an agent procedure to copy & run it via command shell on said agents. Since there is already an agent pointing to that VSA, the /r switch would just tell it to upgrade/install the agent software components (AgentMon.exe, KaUsrTsk.exe, LAN Cache agent assignment components, etc...). The only caveat to that is that if you have merged VSA's from different companies, you would need to create a support ticket and I can send you the proper agnet procedure in that specialized case. Hope this helps.