windows 10 can work with TPM v1.2 or v2.0
windows 7 can only work with TPM v1.2
HP does not support windows 10 on the z620, as such they will not be releasing a 1.2-2.0 TPM update
while hp does not have offical support windows 10 v1803 (and lower) it will install and run fine
if nessary install the latest TPM update from the windows 7 driver selection