Safe? it is official from MS and it is offered as update in Windows Update so I am pretty sure it is very safe 
I thought about using a more older framework to avoid users to need .net 4 (version 4 has more than 2 years already btw), but I found that some stuff I was using like the x64 detection to install the drivers with ease was only available in "hacky"/ugly ways in older versions, so at the end I decided to set 4 for cleanliness.
About the forum, maybe this is a wrong place, I was not sure. If some moderator think it has to be somewere else, please move it