[NAME] Nvidia stopped support for the 800M series cards a long time ago so you cannot download and install the latest updates directly from Nvidia without doing the inf mod. But........there is a weird glitch with the 860M on the Nvidia site that shows that the 860M is compatible with the latest drivers but that's only for a few certain 860M's. Strangely enough, Nvidia released two versions of the 860M. Some of these were based on the Kepler architecture which are the ones that are no longer supported but some of them are Maxwell and these are the GPU's that are still supported, like the 900M series cards. The driver will detect that your card is Kepler so it will not allow the install.  I believe the MXM cards were Kepler and the BGA chips were Maxwell. Since you have an MXM card, you're out of luck.  Also, there is never an issue installing display drivers directly from the GPU manufacturer (Nvidia, AMD, Intel). You do not have to wait months for the laptop manufacturer to release a driver version.   Nvidia GeForce Experience will keep your driver up to date, but only for currently supported cards which yours isn't. I'm not a fan of that program though so I don't install it and I just go straight to Nvidia. 
I have an Alienware 17 R1 from 2014. It has an Intel video card and a Nvidia 860m card installed. I have been unable to update the Nvidia driver to a more recent version? Besides adding the hardware ID to an INF file, has anyone been able to do so? The laptop is running Windows 10 64-bit.
17 R1, cannot update to latest Nvidia drivers?