diff --git a/lib/cwtch/cwtchNotifier.dart b/lib/cwtch/cwtchNotifier.dart
index ebd3979c..acd1a35b 100644
--- a/lib/cwtch/cwtchNotifier.dart
+++ b/lib/cwtch/cwtchNotifier.dart
@@ -149,7 +149,18 @@ class CwtchNotifier {
             profileCN.getProfile(data["ProfileOnion"])?.contactList.getContact(data["GroupID"])!.unreadMessages++;
           }
           profileCN.getProfile(data["ProfileOnion"])?.contactList.getContact(data["GroupID"])!.totalMessages++;
-          profileCN.getProfile(data["ProfileOnion"])?.contactList.updateLastMessageTime(data["GroupID"], DateTime.now());
+          var timestampSent = DateTime.tryParse(data['TimestampSent'])!;
+          // TODO: There are 2 timestamps associated with a new group message - time sent and time received.
+          // Sent refers to the time a profile alleges they sent a message
+          // Received refers to the time we actually saw the message from the server
+          // These can obviously be very different for legitimate reasons.
+          // We also maintain a relative hash-link through PreviousMessageSignature which is the ground truth for
+          // order.
+          // In the future we will want to combine these 3 ordering mechanisms into a cohesive view of the timeline
+          // For now we perform some minimal checks on the sent timestamp to use to provide a useful ordering for honest contacts
+          // and ensure that malicious contacts in groups can only set this timestamp to a value within the range of `last seen message time`
+          // and `local now`.
+          profileCN.getProfile(data["ProfileOnion"])?.contactList.updateLastMessageTime(data["GroupID"], timestampSent.toLocal());
           notificationManager.notify("New Message From Group!");
         } else {
           // from me (already displayed - do not update counter)
diff --git a/lib/model.dart b/lib/model.dart
index 46a8b508..1baa71b0 100644
--- a/lib/model.dart
+++ b/lib/model.dart
@@ -153,12 +153,21 @@ class ContactListState extends ChangeNotifier {
     //} </todo>
   }
 
-  void updateLastMessageTime(String forOnion, DateTime newVal) {
+  void updateLastMessageTime(String forOnion, DateTime newMessageTime) {
     var contact = getContact(forOnion);
     if (contact == null) return;
 
-    contact.lastMessageTime = newVal;
-    resort();
+    // Assert that the new time is after the current last message time AND that
+    // new message time is before the current time.
+    if (newMessageTime.isAfter(contact.lastMessageTime)) {
+      if (newMessageTime.isBefore(DateTime.now().toLocal())) {
+        contact.lastMessageTime = newMessageTime;
+      } else {
+        // Otherwise set the last message time to now...
+        contact.lastMessageTime = DateTime.now().toLocal();
+      }
+      resort();
+    }
   }
 
   List<ContactInfoState> get contacts => _contacts.sublist(0); //todo: copy?? dont want caller able to bypass changenotifier