diff --git a/Signal/src/Loki/View Controllers/DeviceLinkingModal.swift b/Signal/src/Loki/View Controllers/DeviceLinkingModal.swift
index 9ce16ef95..ba52bcf11 100644
--- a/Signal/src/Loki/View Controllers/DeviceLinkingModal.swift	
+++ b/Signal/src/Loki/View Controllers/DeviceLinkingModal.swift	
@@ -166,6 +166,7 @@ final class DeviceLinkingModal : Modal, DeviceLinkingSessionDelegate {
         ThreadUtil.enqueue(linkingAuthorizationMessage)
         SSKEnvironment.shared.messageSender.send(linkingAuthorizationMessage, success: {
             let _ = SSKEnvironment.shared.syncManager.syncAllContacts()
+            _ = SSKEnvironment.shared.syncManager.syncAllGroups()
         }) { _ in
             print("[Loki] Failed to send device link authorization message.")
         }
diff --git a/SignalMessaging/contacts/OWSSyncManager.m b/SignalMessaging/contacts/OWSSyncManager.m
index a7532e918..8acbe1d45 100644
--- a/SignalMessaging/contacts/OWSSyncManager.m
+++ b/SignalMessaging/contacts/OWSSyncManager.m
@@ -16,6 +16,7 @@
 #import <SignalServiceKit/OWSPrimaryStorage.h>
 #import <SignalServiceKit/OWSSyncConfigurationMessage.h>
 #import <SignalServiceKit/OWSSyncContactsMessage.h>
+#import <SignalServiceKit/OWSSyncGroupsMessage.h>
 #import <SignalServiceKit/SSKEnvironment.h>
 #import <SignalServiceKit/SignalAccount.h>
 #import <SignalServiceKit/SignalServiceKit-Swift.h>
@@ -303,6 +304,24 @@ NSString *const kSyncManagerLastContactSyncKey = @"kTSStorageManagerOWSSyncManag
     return promise;
 }
 
+- (AnyPromise *)syncAllGroups
+{
+    OWSSyncGroupsMessage *syncGroupsMessage = [[OWSSyncGroupsMessage alloc] init];
+    AnyPromise *promise = [AnyPromise promiseWithResolverBlock:^(PMKResolver resolve) {
+        [self.messageSender sendMessage:syncGroupsMessage
+            success:^{
+                OWSLogInfo(@"Successfully sent groups sync message.");
+                resolve(@(1));
+            }
+            failure:^(NSError *error) {
+                OWSLogError(@"Failed to send groups sync message with error: %@.", error);
+                resolve(error);
+            }];
+    }];
+    [promise retainUntilComplete];
+    return promise;
+}
+
 @end
 
 NS_ASSUME_NONNULL_END
diff --git a/SignalServiceKit/protobuf/SignalService.proto b/SignalServiceKit/protobuf/SignalService.proto
index aad7efdb2..0c9ee9425 100644
--- a/SignalServiceKit/protobuf/SignalService.proto
+++ b/SignalServiceKit/protobuf/SignalService.proto
@@ -319,6 +319,7 @@ message SyncMessage {
 
   message Groups {
     optional AttachmentPointer blob = 1;
+    optional bytes             data = 101; // Loki
   }
 
   message Blocked {
@@ -399,7 +400,7 @@ message GroupContext {
   optional string            name    = 3;
   repeated string            members = 4;
   optional AttachmentPointer avatar  = 5;
-  repeated string            admins  = 6;
+  repeated string            admins  = 6; // Loki
 }
 
 message ContactDetails {
@@ -435,6 +436,7 @@ message GroupDetails {
   optional uint32 expireTimer = 6;
   optional string color       = 7;
   optional bool   blocked     = 8;
+  repeated string admins      = 9;  // Loki
 }
 
 // Internal - DO NOT SEND
diff --git a/SignalServiceKit/src/Devices/OWSGroupsOutputStream.m b/SignalServiceKit/src/Devices/OWSGroupsOutputStream.m
index 80ba744a7..ba323f7ae 100644
--- a/SignalServiceKit/src/Devices/OWSGroupsOutputStream.m
+++ b/SignalServiceKit/src/Devices/OWSGroupsOutputStream.m
@@ -26,6 +26,7 @@ NS_ASSUME_NONNULL_BEGIN
     [groupBuilder setName:group.groupName];
     [groupBuilder setMembers:group.groupMemberIds];
     [groupBuilder setColor:groupThread.conversationColorName];
+    [groupBuilder setAdmins:group.groupAdminIds];
 
     if ([OWSBlockingManager.sharedManager isGroupIdBlocked:group.groupId]) {
         [groupBuilder setBlocked:YES];
diff --git a/SignalServiceKit/src/Messages/DeviceSyncing/OWSSyncGroupsMessage.m b/SignalServiceKit/src/Messages/DeviceSyncing/OWSSyncGroupsMessage.m
index f76b36f87..5bce40231 100644
--- a/SignalServiceKit/src/Messages/DeviceSyncing/OWSSyncGroupsMessage.m
+++ b/SignalServiceKit/src/Messages/DeviceSyncing/OWSSyncGroupsMessage.m
@@ -11,6 +11,7 @@
 #import "TSGroupThread.h"
 #import <SignalCoreKit/NSDate+OWS.h>
 #import <SignalServiceKit/SignalServiceKit-Swift.h>
+#import "OWSPrimaryStorage.h"
 
 NS_ASSUME_NONNULL_BEGIN
 
@@ -28,22 +29,32 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (nullable SSKProtoSyncMessageBuilder *)syncMessageBuilder
 {
-    if (self.attachmentIds.count != 1) {
-        OWSLogError(@"expected sync groups message to have exactly one attachment, but found %lu",
-            (unsigned long)self.attachmentIds.count);
+    NSError *error;
+    if (self.attachmentIds.count > 1) {
+        OWSLogError(@"Expected sync group message to have one or zero attachments, but found %lu.", (unsigned long)self.attachmentIds.count);
     }
-
-    SSKProtoAttachmentPointer *_Nullable attachmentProto =
-        [TSAttachmentStream buildProtoForAttachmentId:self.attachmentIds.firstObject];
-    if (!attachmentProto) {
-        OWSFailDebug(@"could not build protobuf.");
-        return nil;
+    
+    SSKProtoSyncMessageGroupsBuilder *groupsBuilder;
+    if (self.attachmentIds.count == 0) {
+        SSKProtoAttachmentPointerBuilder *attachmentProtoBuilder = [SSKProtoAttachmentPointer builderWithId:0];
+        SSKProtoAttachmentPointer *attachmentProto = [attachmentProtoBuilder buildAndReturnError:&error];
+        groupsBuilder = [SSKProtoSyncMessageGroups builder];
+        [groupsBuilder setBlob:attachmentProto];
+        __block NSData *data;
+        [OWSPrimaryStorage.sharedManager.dbReadConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
+            data = [self buildPlainTextAttachmentDataWithTransaction:transaction];
+        }];
+        [groupsBuilder setData:data];
+    } else {
+        SSKProtoAttachmentPointer *attachmentProto = [TSAttachmentStream buildProtoForAttachmentId:self.attachmentIds.firstObject];
+        if (attachmentProto == nil) {
+            OWSFailDebug(@"Couldn't build protobuf.");
+            return nil;
+        }
+        groupsBuilder = [SSKProtoSyncMessageGroups builder];
+        [groupsBuilder setBlob:attachmentProto];
     }
 
-    SSKProtoSyncMessageGroupsBuilder *groupsBuilder = [SSKProtoSyncMessageGroups builder];
-    [groupsBuilder setBlob:attachmentProto];
-
-    NSError *error;
     SSKProtoSyncMessageGroups *_Nullable groupsProto = [groupsBuilder buildAndReturnError:&error];
     if (error || !groupsProto) {
         OWSFailDebug(@"could not build protobuf: %@", error);
@@ -68,7 +79,7 @@ NS_ASSUME_NONNULL_BEGIN
     [TSGroupThread
         enumerateCollectionObjectsWithTransaction:transaction
                                        usingBlock:^(id obj, BOOL *stop) {
-                                           if (![obj isKindOfClass:[TSGroupThread class]]) {
+                                           if (![obj isKindOfClass:[TSGroupThread class]] || ((TSGroupThread *)obj).groupModel.groupType != closedGroup) {
                                                if (![obj isKindOfClass:[TSContactThread class]]) {
                                                    OWSLogWarn(
                                                        @"Ignoring non group thread in thread collection: %@", obj);
diff --git a/SignalServiceKit/src/Messages/OWSMessageManager.m b/SignalServiceKit/src/Messages/OWSMessageManager.m
index 4af814e77..a1646c07c 100644
--- a/SignalServiceKit/src/Messages/OWSMessageManager.m
+++ b/SignalServiceKit/src/Messages/OWSMessageManager.m
@@ -1074,7 +1074,7 @@ NS_ASSUME_NONNULL_BEGIN
         [self.identityManager throws_processIncomingSyncMessage:syncMessage.verified transaction:transaction];
     } else if (syncMessage.contacts != nil) {
         if (wasSentByMasterDevice && syncMessage.contacts.data.length > 0) {
-            NSLog(@"[Loki] Received contact sync message.");
+            OWSLogInfo(@"[Loki] Received contact sync message.");
             NSData *data = syncMessage.contacts.data;
             ContactParser *parser = [[ContactParser alloc] initWithData:data];
             NSArray<NSString *> *hexEncodedPublicKeys = [parser parseHexEncodedPublicKeys];
@@ -1102,6 +1102,12 @@ NS_ASSUME_NONNULL_BEGIN
                 }
             }
         }
+    } else if (syncMessage.groups != nil) {
+        if (wasSentByMasterDevice && syncMessage.groups.data.length > 0) {
+            OWSLogInfo(@"[Loki] Received group sync message.");
+            NSData *data = syncMessage.groups.data;
+            //  TODO: decode the data and handle the group info
+        }
     } else {
         OWSLogWarn(@"Ignoring unsupported sync message.");
     }
diff --git a/SignalServiceKit/src/Protos/Generated/SSKProto.swift b/SignalServiceKit/src/Protos/Generated/SSKProto.swift
index c94ca5861..1884be9fd 100644
--- a/SignalServiceKit/src/Protos/Generated/SSKProto.swift
+++ b/SignalServiceKit/src/Protos/Generated/SSKProto.swift
@@ -4551,6 +4551,9 @@ extension SSKProtoSyncMessageContacts.SSKProtoSyncMessageContactsBuilder {
         if let _value = blob {
             builder.setBlob(_value)
         }
+        if let _value = data {
+            builder.setData(_value)
+        }
         return builder
     }
 
@@ -4563,6 +4566,10 @@ extension SSKProtoSyncMessageContacts.SSKProtoSyncMessageContactsBuilder {
         @objc public func setBlob(_ valueParam: SSKProtoAttachmentPointer) {
             proto.blob = valueParam.proto
         }
+        
+        @objc public func setData(_ valueParam: Data) {
+            proto.data = valueParam
+        }
 
         @objc public func build() throws -> SSKProtoSyncMessageGroups {
             return try SSKProtoSyncMessageGroups.parseProto(proto)
@@ -4576,6 +4583,16 @@ extension SSKProtoSyncMessageContacts.SSKProtoSyncMessageContactsBuilder {
     fileprivate let proto: SignalServiceProtos_SyncMessage.Groups
 
     @objc public let blob: SSKProtoAttachmentPointer?
+    
+    @objc public var data: Data? {
+        guard proto.hasData else {
+            return nil
+        }
+        return proto.data
+    }
+    @objc public var hasData: Bool {
+        return proto.hasData
+    }
 
     private init(proto: SignalServiceProtos_SyncMessage.Groups,
                  blob: SSKProtoAttachmentPointer?) {
@@ -6343,6 +6360,16 @@ extension SSKProtoGroupDetailsAvatar.SSKProtoGroupDetailsAvatarBuilder {
         @objc public func setMembers(_ wrappedItems: [String]) {
             proto.members = wrappedItems
         }
+        
+        @objc public func addAdmins(_ valueParam: String) {
+            var items = proto.admins
+            items.append(valueParam)
+            proto.admins = items
+        }
+        
+        @objc public func setAdmins(_ wrappedItems: [String]) {
+            proto.admins = wrappedItems
+        }
 
         @objc public func setAvatar(_ valueParam: SSKProtoGroupDetailsAvatar) {
             proto.avatar = valueParam.proto
@@ -6392,6 +6419,10 @@ extension SSKProtoGroupDetailsAvatar.SSKProtoGroupDetailsAvatarBuilder {
     @objc public var members: [String] {
         return proto.members
     }
+    
+    @objc public var admins: [String] {
+        return proto.admins
+    }
 
     @objc public var active: Bool {
         return proto.active
diff --git a/SignalServiceKit/src/Protos/Generated/SignalService.pb.swift b/SignalServiceKit/src/Protos/Generated/SignalService.pb.swift
index 2b433616e..f81521781 100644
--- a/SignalServiceKit/src/Protos/Generated/SignalService.pb.swift
+++ b/SignalServiceKit/src/Protos/Generated/SignalService.pb.swift
@@ -1945,6 +1945,16 @@ struct SignalServiceProtos_SyncMessage {
     var hasBlob: Bool {return _storage._blob != nil}
     /// Clears the value of `blob`. Subsequent reads from it will return its default value.
     mutating func clearBlob() {_uniqueStorage()._blob = nil}
+    
+    /// Loki
+    var data: Data {
+      get {return _storage._data ?? SwiftProtobuf.Internal.emptyData}
+      set {_uniqueStorage()._data = newValue}
+    }
+    /// Returns true if `data` has been explicitly set.
+    var hasData: Bool {return _storage._data != nil}
+    /// Clears the value of `data`. Subsequent reads from it will return its default value.
+    mutating func clearData() {_uniqueStorage()._data = nil}
 
     var unknownFields = SwiftProtobuf.UnknownStorage()
 
@@ -2534,6 +2544,12 @@ struct SignalServiceProtos_GroupDetails {
     get {return _storage._members}
     set {_uniqueStorage()._members = newValue}
   }
+  
+  ///Loki
+  var admins: [String] {
+    get {return _storage._admins}
+    set {_uniqueStorage()._admins = newValue}
+  }
 
   var avatar: SignalServiceProtos_GroupDetails.Avatar {
     get {return _storage._avatar ?? SignalServiceProtos_GroupDetails.Avatar()}
@@ -4627,10 +4643,12 @@ extension SignalServiceProtos_SyncMessage.Groups: SwiftProtobuf.Message, SwiftPr
   static let protoMessageName: String = SignalServiceProtos_SyncMessage.protoMessageName + ".Groups"
   static let _protobuf_nameMap: SwiftProtobuf._NameMap = [
     1: .same(proto: "blob"),
+    101: .same(proto: "data"),
   ]
 
   fileprivate class _StorageClass {
     var _blob: SignalServiceProtos_AttachmentPointer? = nil
+    var _data: Data? = nil
 
     static let defaultInstance = _StorageClass()
 
@@ -4638,6 +4656,7 @@ extension SignalServiceProtos_SyncMessage.Groups: SwiftProtobuf.Message, SwiftPr
 
     init(copying source: _StorageClass) {
       _blob = source._blob
+      _data = source._data
     }
   }
 
@@ -4654,6 +4673,7 @@ extension SignalServiceProtos_SyncMessage.Groups: SwiftProtobuf.Message, SwiftPr
       while let fieldNumber = try decoder.nextFieldNumber() {
         switch fieldNumber {
         case 1: try decoder.decodeSingularMessageField(value: &_storage._blob)
+        case 101: try decoder.decodeSingularBytesField(value: &_storage._data)
         default: break
         }
       }
@@ -4665,6 +4685,9 @@ extension SignalServiceProtos_SyncMessage.Groups: SwiftProtobuf.Message, SwiftPr
       if let v = _storage._blob {
         try visitor.visitSingularMessageField(value: v, fieldNumber: 1)
       }
+      if let v = _storage._data {
+        try visitor.visitSingularBytesField(value: v, fieldNumber: 101)
+      }
     }
     try unknownFields.traverse(visitor: &visitor)
   }
@@ -4675,6 +4698,7 @@ extension SignalServiceProtos_SyncMessage.Groups: SwiftProtobuf.Message, SwiftPr
         let _storage = _args.0
         let rhs_storage = _args.1
         if _storage._blob != rhs_storage._blob {return false}
+        if _storage._data != rhs_storage._data {return false}
         return true
       }
       if !storagesAreEqual {return false}
@@ -5223,6 +5247,7 @@ extension SignalServiceProtos_GroupDetails: SwiftProtobuf.Message, SwiftProtobuf
     6: .same(proto: "expireTimer"),
     7: .same(proto: "color"),
     8: .same(proto: "blocked"),
+    9: .same(proto: "admins"),
   ]
 
   fileprivate class _StorageClass {
@@ -5234,6 +5259,7 @@ extension SignalServiceProtos_GroupDetails: SwiftProtobuf.Message, SwiftProtobuf
     var _expireTimer: UInt32? = nil
     var _color: String? = nil
     var _blocked: Bool? = nil
+    var _admins: [String] = []
 
     static let defaultInstance = _StorageClass()
 
@@ -5248,6 +5274,7 @@ extension SignalServiceProtos_GroupDetails: SwiftProtobuf.Message, SwiftProtobuf
       _expireTimer = source._expireTimer
       _color = source._color
       _blocked = source._blocked
+      _admins = source._admins
     }
   }
 
@@ -5271,6 +5298,7 @@ extension SignalServiceProtos_GroupDetails: SwiftProtobuf.Message, SwiftProtobuf
         case 6: try decoder.decodeSingularUInt32Field(value: &_storage._expireTimer)
         case 7: try decoder.decodeSingularStringField(value: &_storage._color)
         case 8: try decoder.decodeSingularBoolField(value: &_storage._blocked)
+        case 9: try decoder.decodeRepeatedStringField(value: &_storage._admins)
         default: break
         }
       }
@@ -5303,6 +5331,9 @@ extension SignalServiceProtos_GroupDetails: SwiftProtobuf.Message, SwiftProtobuf
       if let v = _storage._blocked {
         try visitor.visitSingularBoolField(value: v, fieldNumber: 8)
       }
+      if !_storage._admins.isEmpty {
+        try visitor.visitRepeatedStringField(value: _storage._admins, fieldNumber: 9)
+      }
     }
     try unknownFields.traverse(visitor: &visitor)
   }
@@ -5320,6 +5351,7 @@ extension SignalServiceProtos_GroupDetails: SwiftProtobuf.Message, SwiftProtobuf
         if _storage._expireTimer != rhs_storage._expireTimer {return false}
         if _storage._color != rhs_storage._color {return false}
         if _storage._blocked != rhs_storage._blocked {return false}
+        if _storage._admins != rhs_storage._admins {return false}
         return true
       }
       if !storagesAreEqual {return false}
diff --git a/SignalServiceKit/src/TestUtils/OWSMockSyncManager.swift b/SignalServiceKit/src/TestUtils/OWSMockSyncManager.swift
index a3dcb9187..e408b8aaf 100644
--- a/SignalServiceKit/src/TestUtils/OWSMockSyncManager.swift
+++ b/SignalServiceKit/src/TestUtils/OWSMockSyncManager.swift
@@ -9,6 +9,12 @@ import PromiseKit
 
 @objc
 public class OWSMockSyncManager: NSObject, OWSSyncManagerProtocol {
+    public func syncAllGroups() -> AnyPromise {
+        Logger.info("")
+
+        return AnyPromise()
+    }
+    
 
     @objc public func sendConfigurationSyncMessage() {
         Logger.info("")
diff --git a/SignalServiceKit/src/Util/OWSSyncManagerProtocol.h b/SignalServiceKit/src/Util/OWSSyncManagerProtocol.h
index eafb2e6fa..e0b78c36b 100644
--- a/SignalServiceKit/src/Util/OWSSyncManagerProtocol.h
+++ b/SignalServiceKit/src/Util/OWSSyncManagerProtocol.h
@@ -20,6 +20,8 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (AnyPromise *)syncContactsForSignalAccounts:(NSArray<SignalAccount *> *)signalAccounts __attribute__((warn_unused_result));
 
+- (AnyPromise *)syncAllGroups __attribute__((warn_unused_result));
+
 @end
 
 NS_ASSUME_NONNULL_END