diff --git a/SignalServiceKit/src/Messages/OWSBlockingManager.h b/SignalServiceKit/src/Messages/OWSBlockingManager.h
index 424cb5179..e600aadab 100644
--- a/SignalServiceKit/src/Messages/OWSBlockingManager.h
+++ b/SignalServiceKit/src/Messages/OWSBlockingManager.h
@@ -25,6 +25,8 @@ extern NSString *const kNSNotificationName_BlockedPhoneNumbersDidChange;
 
 - (BOOL)isRecipientIdBlocked:(NSString *)recipientId;
 
+- (void)syncBlockedPhoneNumbers;
+
 @end
 
 NS_ASSUME_NONNULL_END
diff --git a/SignalServiceKit/src/Messages/OWSBlockingManager.m b/SignalServiceKit/src/Messages/OWSBlockingManager.m
index 97994c4f3..f09b28e56 100644
--- a/SignalServiceKit/src/Messages/OWSBlockingManager.m
+++ b/SignalServiceKit/src/Messages/OWSBlockingManager.m
@@ -225,6 +225,15 @@ NSString *const kOWSBlockingManager_SyncedBlockedPhoneNumbersKey = @"kOWSBlockin
     [self observeNotifications];
 }
 
+- (void)syncBlockedPhoneNumbers
+{
+    OWSAssert(_blockedPhoneNumberSet);
+
+    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
+        [self sendBlockedPhoneNumbersMessage:self.blockedPhoneNumbers];
+    });
+}
+
 // This method should only be called from within a synchronized block.
 - (void)syncBlockedPhoneNumbersIfNecessary
 {
diff --git a/SignalServiceKit/src/Messages/OWSMessageManager.m b/SignalServiceKit/src/Messages/OWSMessageManager.m
index a44d800b6..b4a9aa2b5 100644
--- a/SignalServiceKit/src/Messages/OWSMessageManager.m
+++ b/SignalServiceKit/src/Messages/OWSMessageManager.m
@@ -602,8 +602,8 @@ NS_ASSUME_NONNULL_BEGIN
                     DDLogError(@"%@ Failed to send Groups response syncMessage with error: %@", self.tag, error);
                 }];
         } else if (syncMessage.request.type == OWSSignalServiceProtosSyncMessageRequestTypeBlocked) {
-            // TODO
-            DDLogWarn(@"%@ Received unsupported request for block list", self.tag);
+            DDLogInfo(@"%@ Received request for block list", self.tag);
+            [_blockingManager syncBlockedPhoneNumbers];
         } else if (syncMessage.request.type == OWSSignalServiceProtosSyncMessageRequestTypeConfiguration) {
             BOOL areReadReceiptsEnabled =
                 [[OWSReadReceiptManager sharedManager] areReadReceiptsEnabledWithTransaction:transaction];