The only indication a web site has of which OS the client is using is the User-Agent header.
You can write rules that use the property:
and match on value you don't want and block.
So a rule like this will block my Android.
Header.Request.Get("User-Agent") matches "*Android*"
Thank you so much,
I was under the impression the user-agent was specific to the browser. I've already created the rule and am just waiting to test.
Thanks again for your prompt help!
It is specific to the browser on the device, but they usuall put in some indication that it's mobile.
This will probably pick up 80% of them if you matches in list:
based on data I see here: