Dmidecode reports information about your system's hardware as described in your system BIOS according to the SMBIOS/DMI standard. This information typically includes system manufacturer, model name, serial number, BIOS version, asset tag, and a lot of other details of varying level of interest and reliability, depending on the manufacturer. This will often include usage status for the CPU sockets, expansion slots and memory module slots, and the list of I/O ports.
Wrong kernel version
"Not in standard version 2.2 kernels" should really read "not in standard version 2.4 kernels." Support for 2.2 kernels was dropped back in version 2.8.0 of lm_sensors, and RHEL 4 is obviously not based on 2.2 kernels anyway.
Re: New wersion is 2.8.8.
We have been admittedly slow to announce the 2.8.8 release here. It is done now, thanks for pointing this out.