For all of you with Intel Wireless adapters.
I ran the utility on this page:-
http://www.intel.com/p/en_US/support/detect/wireless
And for the first time it detected that there was a newer version of my driver.
I have the Intel Centrino wireless-N105 adapter.
I downloaded and clicked on the exe file and within a few seconds the new driver was installed.
Hope I'm not tempting fate but I have not had any dropouts for 4 days either from boot up or from sleep mode.
This driver is not a dedicated Windows 8.1 it says for Windows 8, but its worked for me and I hope it works for all of those with Intel drivers.
The driver covers multiple Intel adapters but the utility will detect the one you have.
I really hope this helps you all.
Acer Aspire E1-571
Intel Corei5
Strange, I've got the same machine. Here the utility says 'This device is unknown or unsupported. Please contact the manufacturer for possible updates.'.
I also tried the manual install. Now I'm on 15.10.5.1. Still no solution.