If asus hasn't updated any drivers for your motherboard etc. you still should not have any issues with upgrading drivers from another legit site that has updated. However, i would first check and see if there are any bios updates available. Have you seen if any are available? And yes i noticed that sometimes if a laptop model gets a bit old, manufacturer sites can sometimes fall behind and not offer any new driver upgrades. They also do this in some instances because they assume most people have upgraded operating systems too and sometimes they do not support the driver upgrades for the newer OS's.

In mose cases it isn't a big deal to try and upgrade some of the drivers even if the newer OS isn't supported. in the early days of Windows 10 launch there were issues with graphics cards drivers in older machines running Windows 10 but Microsoft has done a pretty good job fixing this now.
If all else fails i highly recommend using a program called snappy driver to upgrade your drivers for your machine. The only one i hesitate to upgrade on snappy driver mainly are graphics cards updates in older models. Snappy driver will definitely find all the newer drivers for your machine if they are available and if by chance ASUS has given up adding them to their driver website. Hope this helps !!

P.S. - always have a system restore done before doing any major driver updates on an older machine!!