ESXi 5 and X3650 type 7979

Hi,

I am wondering what would be the safest thing to do.  I have a cluster of mutiple IBM x3650 (type 7979) servers, they are not M2 or M3.  This cluster is actually running ESX 3.5 and I want to upgrade it to the latest version, I will do a clean install.

However, the type 7979 is not listed on the ESXi 5 HCL, but only on the ESX 4.1 HCL.  I don't want to install obsolete software but I want to make sure I won't run into problems with that cluster.

Should I stick to the HCL no matter what and install 4.1 or would it be safe to assume that ESXi 5 will run fine and will be certified sooner or later ?

Thanks!