diff --git a/Mailgun.Models.SignedEvent/SignedEvent.cs b/Mailgun.Models.SignedEvent/SignedEvent.cs
index 0e1d29c..bec01a1 100644
--- a/Mailgun.Models.SignedEvent/SignedEvent.cs
+++ b/Mailgun.Models.SignedEvent/SignedEvent.cs
@@ -10,7 +10,7 @@ namespace Mailgun.Models.SignedEvent
     public class SignedEvent
     {
         [Required]
-        public IMailgunSignature Signature { get; set; }
+        public MailgunSignature Signature { get; set; }
 
         [Required]
         public MailgunEvent EventData { get; set; }