i add Facebook SDK (Swift) to my project. And now i update Xcode 8 and Swift 3. I have error in build time
Module compiled with Swift 2.3 cannot be imported
Have in mind that if you want to use Swift 3 as your main project's language you have to use pods that are either Swift 3, or Swift 2.2-. If you try to use a Swift 2.3 project, they will not compile (as in the error you describe).
So the best thing to do is to use either Swift 3 pods, or Swift 2 (2.1 or 2.2) pods and select Use Legacy SLV for that specific pod (in 'Pods' build setting for the specific target you want to use).