Upgrade Vshpere4.0 to Vshpere5.0 - Affect on BE 2010 R2 Vmware agent

all,

its been couple of years since i last used be 12.5, on to the new job and its be2010r2 being used to backu vshpere 4.0 inf. (200) servers.

i would like to upgrade vshpere 4.0 to 5.0? do i need to keep anything in mind for BE2010 r2? would the upgrade break anything?

i would be good if someone could shed some light on how the be2010 backups vm? where is the agent installed? esx host? virtualcenter? vm?

thanks in advance,