diff --git a/Octokit/Models/Request/NotificationsRequest.cs b/Octokit/Models/Request/NotificationsRequest.cs
index 0bc3375f..42dd07c7 100644
--- a/Octokit/Models/Request/NotificationsRequest.cs
+++ b/Octokit/Models/Request/NotificationsRequest.cs
@@ -21,19 +21,20 @@ namespace Octokit
         public bool Participating { get; set; }
 
         /// <summary>
-        /// Filters out any notifications updated before the given time. Default: DateTimeOffset.MinValue
+        /// Only show notifications updated after the given time. Defaults to the everything if unspecified.
         /// </summary>
-        public DateTimeOffset Since { get; set; }
+        public DateTimeOffset? Since { get; set; }
 
         /// <summary>
-        /// Construct a <see cref="NotificationsRequest"/> object
+        /// Only show notifications updated before the given time.
         /// </summary>
-        public NotificationsRequest()
-        {
-            All = false;
-            Participating = false;
-            Since = DateTimeOffset.MinValue;
-        }
+        /// <remarks>
+        /// This is sent as a timestamp in ISO 8601 format: YYYY-MM-DDTHH:MM:SSZ.
+        /// </remarks>
+        /// <value>
+        /// The before.
+        /// </value>
+        public DateTimeOffset? Before { get; set; }
 
         internal string DebuggerDisplay
         {
diff --git a/ReleaseNotes.md b/ReleaseNotes.md
index d6022bdb..db08949d 100644
--- a/ReleaseNotes.md
+++ b/ReleaseNotes.md
@@ -3,6 +3,7 @@
 * Improved: Added ability to create deploy keys that are read only and can only be used to read repository contents and not write to them - via @haacked
 * Improved: Added `Content` property to `NewTreeItem` to allow specifying content for a tree - via @haacked
 * Improved: Added `Description` property to `NewTeam` to allow specifying a description for a team - via @haacked
+* Improved: Added `Before` property to `NotificationsRequest` to find notifications updated before a specific time - via @haacked
 * Fixed: Bug that prevented sepecifying a commit message for pull request merges - via @haacked
 
 **Breaking Changes:**