I need to upgrade 4 servers to NW 6.5sp4a from nw 5.1sp8.Two servers are
already upgraded to NW 6.5 sp4a.The DS version is across all servers
The master replica server is still Nw 5.1sp8.
Do I need run the Deployment manager and upgrade the schema ????
And PKI do i need to upgrade that ????

Or is it ok to just upgrade the boxes to NW 6.5sp4a.