diff --git a/SignalMessaging/profiles/OWSProfileManager.h b/SignalMessaging/profiles/OWSProfileManager.h
index d52ba1a78..afe8b2faf 100644
--- a/SignalMessaging/profiles/OWSProfileManager.h
+++ b/SignalMessaging/profiles/OWSProfileManager.h
@@ -74,6 +74,7 @@ extern const NSUInteger kOWSProfileManager_MaxAvatarDiameter;
 
 - (nullable OWSAES256Key *)profileKeyForRecipientId:(NSString *)recipientId;
 
+- (nullable NSString *)profileNameForRecipientWithID:(NSString *)recipientID avoidWriteTransaction:(BOOL)avoidWriteTransaction;
 - (nullable NSString *)profileNameForRecipientWithID:(NSString *)recipientID;
 - (nullable NSString *)profileNameForRecipientWithID:(NSString *)recipientID transaction:(YapDatabaseReadWriteTransaction *)transaction;
 
diff --git a/SignalMessaging/profiles/OWSProfileManager.m b/SignalMessaging/profiles/OWSProfileManager.m
index b1776bc6e..58017d509 100644
--- a/SignalMessaging/profiles/OWSProfileManager.m
+++ b/SignalMessaging/profiles/OWSProfileManager.m
@@ -1025,6 +1025,11 @@ typedef void (^ProfileManagerFailureBlock)(NSError *error);
 }
 
 - (nullable NSString *)profileNameForRecipientWithID:(NSString *)recipientID
+{
+    return [self profileNameForRecipientWithID:recipientID avoidingWriteTransaction:NO];
+}
+
+- (nullable NSString *)profileNameForRecipientWithID:(NSString *)recipientID avoidingWriteTransaction:(BOOL)avoidWriteTransaction
 {
     if ([self.tsAccountManager.localNumber isEqualToString:recipientID]) {
         return self.localUserProfile.profileName;
@@ -1047,18 +1052,22 @@ typedef void (^ProfileManagerFailureBlock)(NSError *error);
         }
     }
 
-    __block NSString *result;
+    if (!avoidWriteTransaction) {
+        __block NSString *result;
 
-    [LKStorage writeSyncWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
-        result = [self profileNameForRecipientWithID:recipientID transaction:transaction];
-    } error:nil];
+        [LKStorage writeSyncWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+            result = [self profileNameForRecipientWithID:recipientID transaction:transaction];
+        } error:nil];
 
-    NSString *shortID = [recipientID substringWithRange:NSMakeRange(recipientID.length - 8, 8)];
-    NSString *suffix = [NSString stringWithFormat:@" (...%@)", shortID];
-    if ([result hasSuffix:suffix]) {
-        return [result substringToIndex:result.length - suffix.length];
+        NSString *shortID = [recipientID substringWithRange:NSMakeRange(recipientID.length - 8, 8)];
+        NSString *suffix = [NSString stringWithFormat:@" (...%@)", shortID];
+        if ([result hasSuffix:suffix]) {
+            return [result substringToIndex:result.length - suffix.length];
+        } else {
+            return result;
+        }
     } else {
-        return result;
+        return recipientID;
     }
 }
 
diff --git a/SignalServiceKit/src/Loki/Protocol/Closed Groups/ClosedGroupsProtocol.swift b/SignalServiceKit/src/Loki/Protocol/Closed Groups/ClosedGroupsProtocol.swift
index 4959d68ec..8d6275da6 100644
--- a/SignalServiceKit/src/Loki/Protocol/Closed Groups/ClosedGroupsProtocol.swift	
+++ b/SignalServiceKit/src/Loki/Protocol/Closed Groups/ClosedGroupsProtocol.swift	
@@ -136,6 +136,15 @@ public final class ClosedGroupsProtocol : NSObject {
                     } else {
                         // Establish sessions if needed
                         establishSessionsIfNeeded(with: [String](members), using: transaction)
+                        // Send closed group update messages to any new members using established channels
+                        for member in newMembers {
+                            let thread = TSContactThread.getOrCreateThread(withContactId: member, transaction: transaction)
+                            thread.save(with: transaction)
+                            let closedGroupUpdateMessageKind = ClosedGroupUpdateMessage.Kind.new(groupPublicKey: Data(hex: groupPublicKey), name: name,
+                                groupPrivateKey: Data(hex: groupPrivateKey), senderKeys: [], members: membersAsData, admins: adminsAsData)
+                            let closedGroupUpdateMessage = ClosedGroupUpdateMessage(thread: thread, kind: closedGroupUpdateMessageKind)
+                            messageSenderJobQueue.add(message: closedGroupUpdateMessage, transaction: transaction)
+                        }
                         // Send out the user's new ratchet to all members (minus the removed ones) using established channels
                         let userRatchet = SharedSenderKeysImplementation.shared.generateRatchet(for: groupPublicKey, senderPublicKey: userPublicKey, using: transaction)
                         let userSenderKey = ClosedGroupSenderKey(chainKey: Data(hex: userRatchet.chainKey), keyIndex: userRatchet.keyIndex, publicKey: Data(hex: userPublicKey))
@@ -150,7 +159,7 @@ public final class ClosedGroupsProtocol : NSObject {
                     }
                 }
             }
-        } else {
+        } else if !newMembers.isEmpty {
             seal.fulfill(())
             // Generate ratchets for any new members
             newSenderKeys = newMembers.map { publicKey in
@@ -162,17 +171,24 @@ public final class ClosedGroupsProtocol : NSObject {
                 members: membersAsData, admins: adminsAsData)
             let closedGroupUpdateMessage = ClosedGroupUpdateMessage(thread: thread, kind: closedGroupUpdateMessageKind)
             messageSenderJobQueue.add(message: closedGroupUpdateMessage, transaction: transaction)
-        }
-        // Establish sessions if needed
-        establishSessionsIfNeeded(with: [String](newMembers), using: transaction)
-        // Send closed group update messages to the new members using established channels
-        var allSenderKeys = Storage.getAllClosedGroupSenderKeys(for: groupPublicKey)
-        allSenderKeys.formUnion(newSenderKeys)
-        for member in newMembers {
-            let thread = TSContactThread.getOrCreateThread(withContactId: member, transaction: transaction)
-            thread.save(with: transaction)
-            let closedGroupUpdateMessageKind = ClosedGroupUpdateMessage.Kind.new(groupPublicKey: Data(hex: groupPublicKey), name: name,
-                groupPrivateKey: Data(hex: groupPrivateKey), senderKeys: [ClosedGroupSenderKey](allSenderKeys), members: membersAsData, admins: adminsAsData)
+            // Establish sessions if needed
+            establishSessionsIfNeeded(with: [String](newMembers), using: transaction)
+            // Send closed group update messages to the new members using established channels
+            var allSenderKeys = Storage.getAllClosedGroupSenderKeys(for: groupPublicKey)
+            allSenderKeys.formUnion(newSenderKeys)
+            for member in newMembers {
+                let thread = TSContactThread.getOrCreateThread(withContactId: member, transaction: transaction)
+                thread.save(with: transaction)
+                let closedGroupUpdateMessageKind = ClosedGroupUpdateMessage.Kind.new(groupPublicKey: Data(hex: groupPublicKey), name: name,
+                    groupPrivateKey: Data(hex: groupPrivateKey), senderKeys: [ClosedGroupSenderKey](allSenderKeys), members: membersAsData, admins: adminsAsData)
+                let closedGroupUpdateMessage = ClosedGroupUpdateMessage(thread: thread, kind: closedGroupUpdateMessageKind)
+                messageSenderJobQueue.add(message: closedGroupUpdateMessage, transaction: transaction)
+            }
+        } else {
+            seal.fulfill(())
+            let allSenderKeys = Storage.getAllClosedGroupSenderKeys(for: groupPublicKey)
+            let closedGroupUpdateMessageKind = ClosedGroupUpdateMessage.Kind.info(groupPublicKey: Data(hex: groupPublicKey), name: name,
+                senderKeys: [ClosedGroupSenderKey](allSenderKeys), members: membersAsData, admins: adminsAsData)
             let closedGroupUpdateMessage = ClosedGroupUpdateMessage(thread: thread, kind: closedGroupUpdateMessageKind)
             messageSenderJobQueue.add(message: closedGroupUpdateMessage, transaction: transaction)
         }
@@ -265,7 +281,7 @@ public final class ClosedGroupsProtocol : NSObject {
         let missingSenderKeys = Set(members).subtracting(senderKeys.map { $0.publicKey.toHexString() })
         let userPublicKey = getUserHexEncodedPublicKey()
         if missingSenderKeys.contains(userPublicKey) {
-            establishSessionsIfNeeded(with: [String](missingSenderKeys), using: transaction)
+            establishSessionsIfNeeded(with: [String](members), using: transaction)
             let userRatchet = SharedSenderKeysImplementation.shared.generateRatchet(for: groupPublicKey, senderPublicKey: userPublicKey, using: transaction)
             let userSenderKey = ClosedGroupSenderKey(chainKey: Data(hex: userRatchet.chainKey), keyIndex: userRatchet.keyIndex, publicKey: Data(hex: userPublicKey))
             for member in members {
@@ -283,9 +299,15 @@ public final class ClosedGroupsProtocol : NSObject {
         // Create the group
         let groupID = LKGroupUtilities.getEncodedClosedGroupIDAsData(groupPublicKey)
         let group = TSGroupModel(title: name, memberIds: members, image: nil, groupId: groupID, groupType: .closedGroup, adminIds: admins)
-        let thread = TSGroupThread.getOrCreateThread(with: group, transaction: transaction)
-        thread.usesSharedSenderKeys = true
-        thread.save(with: transaction)
+        let thread: TSGroupThread
+        if let t = TSGroupThread.fetch(uniqueId: TSGroupThread.threadId(fromGroupId: groupID), transaction: transaction) {
+            thread = t
+            thread.setGroupModel(group, with: transaction)
+        } else {
+            thread = TSGroupThread.getOrCreateThread(with: group, transaction: transaction)
+            thread.usesSharedSenderKeys = true
+            thread.save(with: transaction)
+        }
         SSKEnvironment.shared.profileManager.addThread(toProfileWhitelist: thread)
         // Add the group to the user's set of public keys to poll for
         Storage.setClosedGroupPrivateKey(groupPrivateKey.toHexString(), for: groupPublicKey, using: transaction)
@@ -389,7 +411,9 @@ public final class ClosedGroupsProtocol : NSObject {
         // Respond to the request
         print("[Loki] Responding to sender key request from: \(senderPublicKey).")
         SessionManagementProtocol.sendSessionRequestIfNeeded(to: senderPublicKey, using: transaction) // This internally takes care of multi device
-        let userRatchet = SharedSenderKeysImplementation.shared.generateRatchet(for: groupPublicKey, senderPublicKey: userPublicKey, using: transaction)
+        guard let userRatchet = Storage.getClosedGroupRatchet(for: groupPublicKey, senderPublicKey: userPublicKey) else {
+            return print("[Loki] Missing own ratchet.")
+        }
         let userSenderKey = ClosedGroupSenderKey(chainKey: Data(hex: userRatchet.chainKey), keyIndex: userRatchet.keyIndex, publicKey: Data(hex: userPublicKey))
         let thread = TSContactThread.getOrCreateThread(withContactId: senderPublicKey, transaction: transaction)
         thread.save(with: transaction)
@@ -402,23 +426,9 @@ public final class ClosedGroupsProtocol : NSObject {
     private static func handleSenderKeyMessage(_ closedGroupUpdate: SSKProtoDataMessageClosedGroupUpdate, from senderPublicKey: String, using transaction: YapDatabaseReadWriteTransaction) {
         // Prepare
         let groupPublicKey = closedGroupUpdate.groupPublicKey.toHexString()
-        let groupID = LKGroupUtilities.getEncodedClosedGroupIDAsData(groupPublicKey)
-        guard let thread = TSGroupThread.fetch(uniqueId: TSGroupThread.threadId(fromGroupId: groupID), transaction: transaction) else {
-            return print("[Loki] Ignoring closed group sender key for nonexistent group.")
-        }
-        let group = thread.groupModel
         guard let senderKey = closedGroupUpdate.senderKeys.first else {
             return print("[Loki] Ignoring invalid closed group sender key.")
         }
-        // Check that the requesting user is a member of the group
-        var membersAndLinkedDevices: Set<String> = Set(group.groupMemberIds)
-        for member in group.groupMemberIds {
-            let deviceLinks = OWSPrimaryStorage.shared().getDeviceLinks(for: member, in: transaction)
-            membersAndLinkedDevices.formUnion(deviceLinks.flatMap { [ $0.master.publicKey, $0.slave.publicKey ] })
-        }
-        guard membersAndLinkedDevices.contains(senderPublicKey) else {
-            return print("[Loki] Ignoring closed group sender key from non-member.")
-        }
         guard senderKey.publicKey.toHexString() == senderPublicKey else {
             return print("[Loki] Ignoring invalid closed group sender key.")
         }
diff --git a/SignalServiceKit/src/Loki/Protocol/Closed Groups/SharedSenderKeysImplementation.swift b/SignalServiceKit/src/Loki/Protocol/Closed Groups/SharedSenderKeysImplementation.swift
index 170158c6f..59e9d8cb5 100644
--- a/SignalServiceKit/src/Loki/Protocol/Closed Groups/SharedSenderKeysImplementation.swift	
+++ b/SignalServiceKit/src/Loki/Protocol/Closed Groups/SharedSenderKeysImplementation.swift	
@@ -177,7 +177,12 @@ public final class SharedSenderKeysImplementation : NSObject {
             throw RatchetingError.messageKeyMissing(targetKeyIndex: keyIndex, groupPublicKey: groupPublicKey, senderPublicKey: senderPublicKey)
         }
         let aes = try AES(key: Data(hex: messageKey).bytes, blockMode: gcm, padding: .noPadding)
-        return Data(try aes.decrypt(ciphertext.bytes))
+        do {
+            return Data(try aes.decrypt(ciphertext.bytes))
+        } catch {
+            ClosedGroupsProtocol.requestSenderKey(for: groupPublicKey, senderPublicKey: senderPublicKey, using: transaction)
+            throw error
+        }
     }
 
     @objc public func isClosedGroup(_ publicKey: String) -> Bool {
diff --git a/SignalServiceKit/src/Loki/Utilities/DisplayNameUtilities.swift b/SignalServiceKit/src/Loki/Utilities/DisplayNameUtilities.swift
index 2ca72032f..f4866b5be 100644
--- a/SignalServiceKit/src/Loki/Utilities/DisplayNameUtilities.swift
+++ b/SignalServiceKit/src/Loki/Utilities/DisplayNameUtilities.swift
@@ -13,6 +13,15 @@ public final class UserDisplayNameUtilities : NSObject {
     }
     
     // MARK: Sessions
+    @objc(getPrivateChatDisplayNameAvoidWriteTransaction:)
+    public static func getPrivateChatDisplayNameAvoidingWriteTransaction(for publicKey: String) -> String? {
+        if publicKey == userPublicKey {
+            return userDisplayName
+        } else {
+            return SSKEnvironment.shared.profileManager.profileNameForRecipient(withID: publicKey, avoidingWriteTransaction: true)
+        }
+    }
+
     @objc public static func getPrivateChatDisplayName(for publicKey: String) -> String? {
         if publicKey == userPublicKey {
             return userDisplayName
diff --git a/SignalServiceKit/src/Messages/OWSMessageSender.m b/SignalServiceKit/src/Messages/OWSMessageSender.m
index bf73525ba..146e71eda 100644
--- a/SignalServiceKit/src/Messages/OWSMessageSender.m
+++ b/SignalServiceKit/src/Messages/OWSMessageSender.m
@@ -667,7 +667,6 @@ NSString *const OWSMessageSenderRateLimitedException = @"RateLimitedException";
 
     BOOL isSyncMessage = [message isKindOfClass:[OWSOutgoingSyncMessage class]];
     if (thread == nil && !isSyncMessage) {
-        OWSFailDebug(@"Missing thread for non-sync message.");
 
         // The thread has been deleted since the message was enqueued.
         NSError *error = OWSErrorWithCodeDescription(OWSErrorCodeMessageSendNoValidRecipients,
diff --git a/SignalServiceKit/src/Messages/TSGroupModel.m b/SignalServiceKit/src/Messages/TSGroupModel.m
index c2e233665..6157d55b4 100644
--- a/SignalServiceKit/src/Messages/TSGroupModel.m
+++ b/SignalServiceKit/src/Messages/TSGroupModel.m
@@ -133,7 +133,7 @@ const int32_t kGroupIdLength = 16;
 
     if ([membersWhoLeft count] > 0) {
         NSArray *oldMembersNames = [[membersWhoLeft allObjects] map:^NSString*(NSString* item) {
-            return [LKUserDisplayNameUtilities getPrivateChatDisplayNameFor:item];
+            return [LKUserDisplayNameUtilities getPrivateChatDisplayNameAvoidWriteTransaction:item];
         }];
         updatedGroupInfoString = [updatedGroupInfoString
                                   stringByAppendingString:[NSString
diff --git a/SignalServiceKit/src/Protocols/ProfileManagerProtocol.h b/SignalServiceKit/src/Protocols/ProfileManagerProtocol.h
index b19d1af21..01694420a 100644
--- a/SignalServiceKit/src/Protocols/ProfileManagerProtocol.h
+++ b/SignalServiceKit/src/Protocols/ProfileManagerProtocol.h
@@ -14,6 +14,7 @@ NS_ASSUME_NONNULL_BEGIN
 - (OWSAES256Key *)localProfileKey;
 
 - (nullable NSString *)localProfileName;
+- (nullable NSString *)profileNameForRecipientWithID:(NSString *)recipientID avoidingWriteTransaction:(BOOL)avoidWriteTransaction;
 - (nullable NSString *)profileNameForRecipientWithID:(NSString *)recipientID;
 - (nullable NSString *)profileNameForRecipientWithID:(NSString *)recipientID transaction:(YapDatabaseReadWriteTransaction *)transaction;
 - (nullable NSString *)profilePictureURL;