diff --git a/SessionMessagingKit/Messages/Message.swift b/SessionMessagingKit/Messages/Message.swift
index f39136b4a..3ea4b46f0 100644
--- a/SessionMessagingKit/Messages/Message.swift
+++ b/SessionMessagingKit/Messages/Message.swift
@@ -10,6 +10,7 @@ public class Message : NSObject, NSCoding { // NSObject/NSCoding conformance is
     public var sender: String?
     public var groupPublicKey: String?
     public var openGroupServerMessageID: UInt64?
+    public var openGroupServerTimestamp: UInt64?
 
     public var ttl: UInt64 { 2 * 24 * 60 * 60 * 1000 }
     public var isSelfSendValid: Bool { false }
@@ -30,6 +31,10 @@ public class Message : NSObject, NSCoding { // NSObject/NSCoding conformance is
         if let sentTimestamp = coder.decodeObject(forKey: "sentTimestamp") as! UInt64? { self.sentTimestamp = sentTimestamp }
         if let receivedTimestamp = coder.decodeObject(forKey: "receivedTimestamp") as! UInt64? { self.receivedTimestamp = receivedTimestamp }
         if let recipient = coder.decodeObject(forKey: "recipient") as! String? { self.recipient = recipient }
+        if let sender = coder.decodeObject(forKey: "sender") as! String? { self.sender = sender }
+        if let groupPublicKey = coder.decodeObject(forKey: "groupPublicKey") as! String? { self.groupPublicKey = groupPublicKey }
+        if let openGroupServerMessageID = coder.decodeObject(forKey: "openGroupServerMessageID") as! UInt64? { self.openGroupServerMessageID = openGroupServerMessageID }
+        if let openGroupServerTimestamp = coder.decodeObject(forKey: "openGroupServerTimestamp") as! UInt64? { self.openGroupServerTimestamp = openGroupServerTimestamp }
     }
 
     public func encode(with coder: NSCoder) {
@@ -38,6 +43,10 @@ public class Message : NSObject, NSCoding { // NSObject/NSCoding conformance is
         coder.encode(sentTimestamp, forKey: "sentTimestamp")
         coder.encode(receivedTimestamp, forKey: "receivedTimestamp")
         coder.encode(recipient, forKey: "recipient")
+        coder.encode(sender, forKey: "sender")
+        coder.encode(groupPublicKey, forKey: "groupPublicKey")
+        coder.encode(openGroupServerMessageID, forKey: "openGroupServerMessageID")
+        coder.encode(openGroupServerTimestamp, forKey: "openGroupServerTimestamp")
     }
 
     // MARK: Proto Conversion
diff --git a/SessionMessagingKit/Messages/Signal/TSIncomingMessage+Conversion.swift b/SessionMessagingKit/Messages/Signal/TSIncomingMessage+Conversion.swift
index 48027531e..32916187e 100644
--- a/SessionMessagingKit/Messages/Signal/TSIncomingMessage+Conversion.swift
+++ b/SessionMessagingKit/Messages/Signal/TSIncomingMessage+Conversion.swift
@@ -19,7 +19,7 @@ public extension TSIncomingMessage {
             expiresInSeconds: !isOpenGroupMessage ? expiration : 0, // Ensure we don't ever expire open group messages
             quotedMessage: quotedMessage,
             linkPreview: linkPreview,
-            serverTimestamp: nil,
+            serverTimestamp: visibleMessage.openGroupServerTimestamp as NSNumber?,
             wasReceivedByUD: true
         )
         result.openGroupServerMessageID = openGroupServerMessageID
diff --git a/SessionMessagingKit/Messages/Signal/TSInteraction.h b/SessionMessagingKit/Messages/Signal/TSInteraction.h
index d21b25555..1d67d12c0 100644
--- a/SessionMessagingKit/Messages/Signal/TSInteraction.h
+++ b/SessionMessagingKit/Messages/Signal/TSInteraction.h
@@ -41,8 +41,6 @@ NSString *NSStringFromOWSInteractionType(OWSInteractionType value);
 @property (nonatomic, readonly) uint64_t receivedAtTimestamp;
 @property (nonatomic, readonly) BOOL shouldUseServerTime;
 
-- (void)setServerTimestampToReceivedTimestamp:(uint64_t)receivedAtTimestamp;
-
 - (uint64_t)timestampForUI;
 
 - (NSDate *)receivedAtDate;
diff --git a/SessionMessagingKit/Messages/Signal/TSInteraction.m b/SessionMessagingKit/Messages/Signal/TSInteraction.m
index 2c21a3997..d71496f1b 100644
--- a/SessionMessagingKit/Messages/Signal/TSInteraction.m
+++ b/SessionMessagingKit/Messages/Signal/TSInteraction.m
@@ -169,8 +169,8 @@ NSString *NSStringFromOWSInteractionType(OWSInteractionType value)
 
 - (uint64_t)timestampForUI
 {
-    if (_shouldUseServerTime) {
-        return _receivedAtTimestamp;
+    if ([self isKindOfClass:TSIncomingMessage.class] && ((TSIncomingMessage *) self).isOpenGroupMessage) {
+        return ((TSIncomingMessage *) self).serverTimestamp.unsignedLongLongValue;
     }
     return _timestamp;
 }
@@ -180,14 +180,11 @@ NSString *NSStringFromOWSInteractionType(OWSInteractionType value)
     return self.timestamp;
 }
 
-- (void)setServerTimestampToReceivedTimestamp:(uint64_t)receivedAtTimestamp
-{
-    _shouldUseServerTime = YES;
-    _receivedAtTimestamp = receivedAtTimestamp;
-}
-
 - (NSDate *)receivedAtDate
 {
+    if ([self isKindOfClass:TSIncomingMessage.class] && ((TSIncomingMessage *) self).isOpenGroupMessage) {
+        return [NSDate ows_dateWithMillisecondsSince1970:((TSIncomingMessage *) self).serverTimestamp.unsignedLongLongValue];
+    }
     return [NSDate ows_dateWithMillisecondsSince1970:self.receivedAtTimestamp];
 }
 
@@ -199,13 +196,10 @@ NSString *NSStringFromOWSInteractionType(OWSInteractionType value)
     // In open groups messages should be sorted by server timestamp. `sortId` represents the order in which messages
     // were processed. Since in the open group poller we sort messages by their server timestamp, sorting by `sortId` is
     // effectively the same as sorting by server timestamp.
-    if ([self isKindOfClass:TSMessage.class] && ((TSMessage *)self).isOpenGroupMessage) {
-        sortId1 = self.sortId;
-        sortId2 = other.sortId;
-    } else {
-        sortId1 = self.timestamp;
-        sortId2 = other.timestamp;
-    }
+    // sortId == serverTimestamp for open group messages.
+    // sortId == timestamp (the sent timestamp) for one-to-one and closed group messages.
+    sortId1 = self.sortId;
+    sortId2 = other.sortId;
 
     if (sortId1 > sortId2) {
         return NSOrderedDescending;
@@ -229,6 +223,14 @@ NSString *NSStringFromOWSInteractionType(OWSInteractionType value)
                      (unsigned long)self.timestamp];
 }
 
+- (uint64_t)sortId
+{
+    if ([self isKindOfClass:TSIncomingMessage.class] && ((TSIncomingMessage *) self).isOpenGroupMessage) {
+        return ((TSIncomingMessage *) self).serverTimestamp.unsignedLongLongValue;
+    }
+    return self.timestamp;
+}
+
 - (void)saveWithTransaction:(YapDatabaseReadWriteTransaction *)transaction
 {
     if (!self.uniqueId) {
diff --git a/SessionMessagingKit/Sending & Receiving/MessageReceiver.swift b/SessionMessagingKit/Sending & Receiving/MessageReceiver.swift
index 20daff6db..3547681f3 100644
--- a/SessionMessagingKit/Sending & Receiving/MessageReceiver.swift	
+++ b/SessionMessagingKit/Sending & Receiving/MessageReceiver.swift	
@@ -146,6 +146,9 @@ public enum MessageReceiver {
             message.recipient = userPublicKey
             message.sentTimestamp = envelope.timestamp
             message.receivedTimestamp = NSDate.millisecondTimestamp()
+            if isOpenGroupMessage {
+                message.openGroupServerTimestamp = envelope.serverTimestamp
+            }
             message.groupPublicKey = groupPublicKey
             message.openGroupServerMessageID = openGroupMessageServerID
             // Validate