Our initial rollout is using the EPDM 2011 SP0, which is what was on the installation DVD.  I'd like to start planning to move to the latest service pack, but I want to understand the proper procedure before I start changing things.

Does a SP update require changes to the server(s), and if so, need they be shutdown or restarted?

Does each client need to be updated individually?

What pitfalls may occur as a result of such an update?

Thanks.