# System.Runtime.Versioning

``` diff
 namespace System.Runtime.Versioning {
+    [AttributeUsageAttribute(AttributeTargets.Assembly | AttributeTargets.Class | AttributeTargets.Constructor | AttributeTargets.Enum | AttributeTargets.Event | AttributeTargets.Field | AttributeTargets.Interface | AttributeTargets.Method | AttributeTargets.Module | AttributeTargets.Property | AttributeTargets.Struct, AllowMultiple=true, Inherited=false)]
+    public sealed class ObsoletedOSPlatformAttribute : OSPlatformAttribute {
+        public ObsoletedOSPlatformAttribute(string platformName);
+        public ObsoletedOSPlatformAttribute(string platformName, string? message);
+        public string Message { get; }
+        public string Url { get; set; }
+    }
     [AttributeUsageAttribute(AttributeTargets.Assembly | AttributeTargets.Class | AttributeTargets.Constructor | AttributeTargets.Enum | AttributeTargets.Event | AttributeTargets.Field | AttributeTargets.Interface | AttributeTargets.Method | AttributeTargets.Module | AttributeTargets.Property | AttributeTargets.Struct, AllowMultiple=true, Inherited=false)]
     public sealed class UnsupportedOSPlatformAttribute : OSPlatformAttribute {
+        public UnsupportedOSPlatformAttribute(string platformName, string? message);
+        public string? Message { get; }
     }
 }
```

