# System.Security.Cryptography.X509Certificates

``` diff
 namespace System.Security.Cryptography.X509Certificates {
     public sealed class X509Certificate2UI {
-        public static X509Certificate2Collection SelectFromCollection(X509Certificate2Collection certificates, string title, string message, X509SelectionFlag selectionFlag);
+        public static X509Certificate2Collection SelectFromCollection(X509Certificate2Collection certificates, string? title, string? message, X509SelectionFlag selectionFlag);
-        public static X509Certificate2Collection SelectFromCollection(X509Certificate2Collection certificates, string title, string message, X509SelectionFlag selectionFlag, IntPtr hwndParent);
+        public static X509Certificate2Collection SelectFromCollection(X509Certificate2Collection certificates, string? title, string? message, X509SelectionFlag selectionFlag, IntPtr hwndParent);
     }
 }
```

