Upgrade from ESX 4.1 to ESXi 5.5 VMFS3

Hi All,

I am looking at upgrading an environment from ESX 4.1 to ESXi 5.5.

I am going to create a new 5.5 vCenter server and connect the 4.1 hosts so that i can vMotion and not have any downtime. I will then complete a fresh install of ESXi 5.5 1 host at a time.

My question is if VMFS3 is supported with ESXi 5.5? When i configure the host to connect to the SAN the volumes are currently VMFS3? I don't want them to be formatted automatically resulting in downtime?

Thanks