MissingMethodException when initializing Unity ads on IOS

i had working reward video in project, then i updated it to 2018.3 and now i get > MissingMethodException: Initializing Unity Ads. UnityEngine.Advertisements.Creator:CreatePlatform() UnityEngine.Advertisements.Advertisement:.cctor() UnityEngine.Advertisements.Creator:LoadRuntime()> (Filename: ./Runtime/Export/Debug.bindings.h Line: 45)> Uploading Crash Report> MissingMethodException: Method not found: 'Default constructor not found...ctor() of UnityEngine.Advertisements.Platform'.> at System.Activator.CreateInstance (System.Type type, Boolean nonPublic) [0x00000] in :0 > at UnityEngine.Advertisements.Creator.CreatePlatform () [0x00000] in :0 > at UnityEngine.Advertisements.Advertisement..cctor () [0x00000] in :0 > at UnityEngine.Advertisements.Creator.LoadRuntime () [0x00000] in :0 > UnityEngine.Advertisements.Creator:CreatePlatform()> UnityEngine.Advertisements.Advertisement:.cctor()> UnityEngine.Advertisements.Creator:LoadRuntime()> (Filename: currently not available on il2cpp Line: -1) I quess some code strips, and i add to link.xml that: but i still have same exception. In inspector all working correct. If i downgrade to 2018.2 i will loose all prefabs. Does anybody knows what can i do to get working reward video?