Help with an error Cardboard SDK "warning CS0618"

Hello all
I am getting this error far too often. I have the latest Cardboard SDK and latest Unity update. Anyone have a fix?
Assets/Cardboard/Scripts/VRDevices/BaseCardboardDevice.cs(122,8): warning CS0618: `UnityEngine.GL.IssuePluginEvent(int)' is obsolete: `IssuePluginEvent(eventID) is deprecated. Use IssuePluginEvent(callback, eventID) instead.'
Thanks, Henry