I just tried the "Free" upgrade... I got to a spot where I could not get past. You can go to MS's site and download the 32bit installer which will download the OS and start to install. It will ask you if you want a clean install or keep all your apps and files. Since I just upgraded my 31 to a 512GB SSD and reloaded W7... I opted to keep everything.
Then I get the dreaded, "Uninstall Intel Dynamic Power Performance Management" because it is not compatible with W10. So I uninstall it... It still won't install. So I stop the installation thinking a reboot is necessary. So I do that and redownload the OS to install... It still read the Intel program and stops the installation.
I just thought I would give this a try. So I recon I will wait and pay for the complete OS install as the free OS is only available for upgrade at present.
Just wanted to let you guys know. I read where someone else tried the install on a different Toughbook and ran into the same issue. So I think clean installs will be the only way to install W10 on your Toughbook.