Latitude e7470, BitLocker, Windows 7

We just purchased a new Latitude e7470. We have installed Windows 7 Enterprise on it. TPM is enabled in the BIOS with the default settings. Windows 7 is installed in Legacy mode instead of UEFI. BIOS version is 1.9.4, the latest version. I noticed this has TPM 2.0 whereas our previous e7450s had TPM 1.2. I'm not entirely sure what the difference is, but I'm assuming it's enough for it to not work.

Anyways, when I enable TPM for the OS drive, I get this message:

"The Trust Platform Module (TPM) on this computer does not work with the current BIOS. Contact the computer manufacturer for BIOS upgrade instructions."

I have the latest version of the BIOS. My only guess is Windows 7 is not fully compatible with TPM 2.0? I installed a hotfix, but that only appears to have installed a driver for TPM. How can I fix this?