How to change the target framework to Unity 3.5 .net Subset Base Class Libraries in the MonoDevelop-Unity?

[diegol11]

Unity3D ver. is 5.3.4f1.
I had failed to find.

It is necessary to build lidgren dll files.
https://github.com/lidgren/lidgren-network-gen3/wiki/Unity3D

my screenshot.

[ChaimHong]

same need help