Hi, I am Upgrading a project, from an old Ad platform to a new one, but I encounter a little problem, I use to add to the project an .jar file with all the Google play services, but now, on the SDK folder everything is split, but now, when I add at least google-play-services-11.0.4.arr, when I tried to build it breaks, that there is not .jar on the arr… I guess what I need is a explanation on how now it works 
Thanks in advance 
In the past you used to include google_play_services.jar which contained all the functionality for the different google play services.
Since you are probably not using all the functionality, and due to other issues (e.g: 65k method dex ref count), they decided to split the libraries into a set of .aar files. this approach is more “modular” as you can pick exactly which library you need (ads, authentication, google drive integration, etc)
OK I got it, actually I think that is a big improvement, but what about that error, that Unity cant extract the .jar from google services? my .aar that only has google play it is 1KB
This probably means the .aar file you have doesn’t contain any code.