I have a custom iPart that calls an SSRS report, however it was working fine in 15.1, but we have since upgraded the client to 15.2.15. Within the Display.ascx page I get the following error :
Error on Page Load: System.MissingMethodException: Method not found: 'System.String.Asi.Security.AppIdentity.get_ContactMaster()'. at CommonUtility.GetLoggedInIMISID();