Before you start to panic about backward compatibility with existing drivers the lockdown is only going to be enforced on new installations of Windows 10. If you simply upgrade an existing system then the OS will take over the drivers that are already installed. Only new installations, i.e. installing all drivers from scratch, will enforce the new rules from Windows 10 version 1607.
Be warned, if you need to do a fresh install of Windows 10 in the future you might find that your existing drivers are rejected.
There's an xkcd for that: https://xkcd.com/1144/