Need an earlier BIOS version for my Dell Latitude E4310

I am trying to upgrade the BIOS on this laptop to the latest version, which is 14.  The laptop currently has version 04 installed.  But when I try to install the latest BIOS file, I get an error message that I must install version 07 first.  However, the only BIOS file listed on the downloads page is version 14.  Where do I find earlier versions of the BIOS so I can get my system updated to the latest BIOS?