Error FB.Init using the Facebook Unity sdk 7.11

I used Unity 5.6. I need to upgrade Facebook Unity SDK from 7.8 to 7.11 but encounter the issue when calling FB.Init

FileNotFoundException: Could not load file or assembly 'Facebook.Unity.IOS' or one of its dependencies. The system cannot find the file specified. at System.AppDomain.InternalSetContext (System.Runtime.Remoting.Contexts.Context context) [0x00000] in :0 at System.AppDomain.Load (System.String assemblyString) [0x00000] in :0 at Facebook.Unity.Mobile.IOS.IOSFacebook.GetIOSWrapper () [0x00000] in :0 at Facebook.Unity.Mobile.IOS.IOSFacebook..ctor () [0x00000] in :0 at Facebook.Unity.Mobile.IOS.IOSFacebookLoader.get_FBGameObject () [0x00000] in :0 at Facebook.Unity.FB+CompiledFacebookLoader.Start () [0x00000] in :0

I am sure that I click targeting iOS for Facebook.Unity.IOS.dll
I followed the instruction from the guy here: https://answers.unity.com/questions/1392096/fbinit-is-failing-while-building-for-ios.html but doesn't work as well.
No upgrade guide for facebook Unity sdk in the official FB pages. Have anyone encountered the same issue can help?