I downloaded the lastest version 2018.3 and I added external DLL.. It compiled in framework 4.x and in new Unity is super. However, I would like to add vuforia, and It's not possible to run on 4.x but I have to switch at 3.5. When I switched in player settings, vuforia is okay, but the library I cannot use. I tried also dissasembly dll and load to VS and recompile, but I got a some errors and I'm not able to finish that.
Thanks for any help!