diff --git a/windows/WinUI/ZeroTierPeer.cs b/windows/WinUI/ZeroTierPeer.cs
index ba925a6fb..5377f74a0 100644
--- a/windows/WinUI/ZeroTierPeer.cs
+++ b/windows/WinUI/ZeroTierPeer.cs
@@ -13,10 +13,10 @@ namespace WinUI
         public string Address { get; set; }
 
         [JsonProperty("lastUnicastFrame")]
-        public int LastUnicastFrame { get; set; }
+        public UInt64 LastUnicastFrame { get; set; }
 
         [JsonProperty("lastMulticastFrame")]
-        public int LastMulticastFrame { get; set; }
+        public UInt64 LastMulticastFrame { get; set; }
 
         [JsonProperty("versionMajor")]
         public int VersionMajor { get; set; }
diff --git a/windows/WinUI/ZeroTierPeerPhysicalPath.cs b/windows/WinUI/ZeroTierPeerPhysicalPath.cs
index 51bb3d5bd..3eaa80266 100644
--- a/windows/WinUI/ZeroTierPeerPhysicalPath.cs
+++ b/windows/WinUI/ZeroTierPeerPhysicalPath.cs
@@ -13,10 +13,10 @@ namespace WinUI
         public string Address { get; set; }
 
         [JsonProperty("lastSend")]
-        public int LastSend { get; set; }
+        public UInt64 LastSend { get; set; }
 
         [JsonProperty("lastReceive")]
-        public int LastReceive { get; set; }
+        public UInt64 LastReceive { get; set; }
 
         [JsonProperty("fixed")]
         public bool Fixed { get; set; }