diff --git a/src/Messages/TSMessagesManager.m b/src/Messages/TSMessagesManager.m
index e3bdce81b..bf2129a85 100644
--- a/src/Messages/TSMessagesManager.m
+++ b/src/Messages/TSMessagesManager.m
@@ -336,19 +336,6 @@ NS_ASSUME_NONNULL_BEGIN
         NSString *recipientId = messageEnvelope.source;
         int deviceId = messageEnvelope.sourceDevice;
         dispatch_async([OWSDispatch sessionStoreQueue], ^{
-            if (![storageManager containsSession:recipientId deviceId:deviceId]) {
-                __block TSErrorMessage *errorMessage;
-                [self.dbConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
-                    errorMessage =
-                        [TSErrorMessage missingSessionWithEnvelope:messageEnvelope withTransaction:transaction];
-                    [errorMessage saveWithTransaction:transaction];
-                }];
-                [self notififyForErrorMessage:errorMessage withEnvelope:messageEnvelope];
-                DDLogError(@"Skipping message envelope for unknown session.");
-                completion(nil);
-                return;
-            }
-
             // DEPRECATED - Remove after all clients have been upgraded.
             NSData *encryptedData
                 = messageEnvelope.hasContent ? messageEnvelope.content : messageEnvelope.legacyMessage;
diff --git a/src/Storage/AxolotlStore/TSStorageManager+SessionStore.h b/src/Storage/AxolotlStore/TSStorageManager+SessionStore.h
index b33f33119..741146204 100644
--- a/src/Storage/AxolotlStore/TSStorageManager+SessionStore.h
+++ b/src/Storage/AxolotlStore/TSStorageManager+SessionStore.h
@@ -7,6 +7,8 @@
 
 @interface TSStorageManager (SessionStore) <SessionStore>
 
+- (void)archiveAllSessionsForContact:(NSString *)contactIdentifier;
+
 #pragma mark - debug
 
 - (void)printAllSessions;
diff --git a/src/Storage/AxolotlStore/TSStorageManager+SessionStore.m b/src/Storage/AxolotlStore/TSStorageManager+SessionStore.m
index 74e26fc53..2e6f3690b 100644
--- a/src/Storage/AxolotlStore/TSStorageManager+SessionStore.m
+++ b/src/Storage/AxolotlStore/TSStorageManager+SessionStore.m
@@ -3,6 +3,7 @@
 //
 
 #import "TSStorageManager+SessionStore.h"
+#import <AxolotlKit/SessionRecord.h>
 
 NSString *const TSStorageManagerSessionStoreCollection = @"TSStorageManagerSessionStoreCollection";
 NSString *const kSessionStoreDBConnectionKey = @"kSessionStoreDBConnectionKey";
@@ -158,6 +159,35 @@ void AssertIsOnSessionStoreQueue()
     }];
 }
 
+- (void)archiveAllSessionsForContact:(NSString *)contactIdentifier
+{
+    AssertIsOnSessionStoreQueue();
+
+    DDLogInfo(@"[TSStorageManager (SessionStore)] archiving all sessions for contact: %@", contactIdentifier);
+
+    __block NSDictionary<NSNumber *, SessionRecord *> *sessionRecords;
+    [self.sessionDBConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+        sessionRecords =
+            [transaction objectForKey:contactIdentifier inCollection:TSStorageManagerSessionStoreCollection];
+
+
+        for (id deviceId in sessionRecords) {
+            id object = sessionRecords[deviceId];
+            if (![object isKindOfClass:[SessionRecord class]]) {
+                OWSFail(@"Unexpected object in session dict: %@", object);
+                continue;
+            }
+
+            SessionRecord *sessionRecord = (SessionRecord *)object;
+            [sessionRecord archiveCurrentState];
+        }
+
+        [transaction setObject:sessionRecords
+                        forKey:contactIdentifier
+                  inCollection:TSStorageManagerSessionStoreCollection];
+    }];
+}
+
 #pragma mark - debug
 
 - (void)printAllSessions