diff --git a/Signal/src/ViewControllers/ConversationView/ConversationViewController.m b/Signal/src/ViewControllers/ConversationView/ConversationViewController.m
index 1a71995064..379ff523ea 100644
--- a/Signal/src/ViewControllers/ConversationView/ConversationViewController.m
+++ b/Signal/src/ViewControllers/ConversationView/ConversationViewController.m
@@ -291,6 +291,10 @@ typedef NS_ENUM(NSInteger, MessagesRangeSizeMode) {
                                              selector:@selector(yapDatabaseModified:)
                                                  name:YapDatabaseModifiedNotification
                                                object:nil];
+    [[NSNotificationCenter defaultCenter] addObserver:self
+                                             selector:@selector(yapDatabaseModified:)
+                                                 name:YapDatabaseModifiedExternallyNotification
+                                               object:nil];
     [[NSNotificationCenter defaultCenter] addObserver:self
                                              selector:@selector(applicationWillEnterForeground:)
                                                  name:UIApplicationWillEnterForegroundNotification
diff --git a/Signal/src/ViewControllers/HomeViewController.m b/Signal/src/ViewControllers/HomeViewController.m
index 9e96251fce..1f050d0d69 100644
--- a/Signal/src/ViewControllers/HomeViewController.m
+++ b/Signal/src/ViewControllers/HomeViewController.m
@@ -136,6 +136,10 @@ typedef NS_ENUM(NSInteger, CellState) { kArchiveState, kInboxState };
                                              selector:@selector(yapDatabaseModified:)
                                                  name:YapDatabaseModifiedNotification
                                                object:nil];
+    [[NSNotificationCenter defaultCenter] addObserver:self
+                                             selector:@selector(yapDatabaseModified:)
+                                                 name:YapDatabaseModifiedExternallyNotification
+                                               object:nil];
 }
 
 - (void)dealloc
diff --git a/Signal/src/ViewControllers/OWSLinkedDevicesTableViewController.m b/Signal/src/ViewControllers/OWSLinkedDevicesTableViewController.m
index 1ff14c2b35..1c3d41dcd0 100644
--- a/Signal/src/ViewControllers/OWSLinkedDevicesTableViewController.m
+++ b/Signal/src/ViewControllers/OWSLinkedDevicesTableViewController.m
@@ -66,7 +66,10 @@ int const OWSLinkedDevicesTableViewControllerSectionAddDevice = 1;
                                              selector:@selector(yapDatabaseModified:)
                                                  name:YapDatabaseModifiedNotification
                                                object:self.dbConnection.database];
-
+    [[NSNotificationCenter defaultCenter] addObserver:self
+                                             selector:@selector(yapDatabaseModified:)
+                                                 name:YapDatabaseModifiedExternallyNotification
+                                               object:self.dbConnection.database];
 
     self.refreshControl = [UIRefreshControl new];
     [self.refreshControl addTarget:self action:@selector(refreshDevices) forControlEvents:UIControlEventValueChanged];
diff --git a/Signal/src/ViewControllers/ThreadViewHelper.m b/Signal/src/ViewControllers/ThreadViewHelper.m
index f0aa727f0f..5af480c06e 100644
--- a/Signal/src/ViewControllers/ThreadViewHelper.m
+++ b/Signal/src/ViewControllers/ThreadViewHelper.m
@@ -72,6 +72,10 @@ NS_ASSUME_NONNULL_BEGIN
                                                  selector:@selector(yapDatabaseModified:)
                                                      name:YapDatabaseModifiedNotification
                                                    object:database];
+        [[NSNotificationCenter defaultCenter] addObserver:self
+                                                 selector:@selector(yapDatabaseModified:)
+                                                     name:YapDatabaseModifiedExternallyNotification
+                                                   object:database];
     }
     return _uiDatabaseConnection;
 }
diff --git a/SignalServiceKit/src/Messages/OWSMessageManager.m b/SignalServiceKit/src/Messages/OWSMessageManager.m
index b812e5f00c..b8f716f975 100644
--- a/SignalServiceKit/src/Messages/OWSMessageManager.m
+++ b/SignalServiceKit/src/Messages/OWSMessageManager.m
@@ -125,6 +125,10 @@ NS_ASSUME_NONNULL_BEGIN
                                              selector:@selector(yapDatabaseModified:)
                                                  name:YapDatabaseModifiedNotification
                                                object:nil];
+    [[NSNotificationCenter defaultCenter] addObserver:self
+                                             selector:@selector(yapDatabaseModified:)
+                                                 name:YapDatabaseModifiedExternallyNotification
+                                               object:nil];
 }
 
 - (void)yapDatabaseModified:(NSNotification *)notification
diff --git a/SignalServiceKit/src/Storage/TSDatabaseView.h b/SignalServiceKit/src/Storage/TSDatabaseView.h
index f22d9f80aa..19a81af670 100644
--- a/SignalServiceKit/src/Storage/TSDatabaseView.h
+++ b/SignalServiceKit/src/Storage/TSDatabaseView.h
@@ -25,6 +25,8 @@ extern NSString *const TSSecondaryDevicesDatabaseViewExtensionName;
 // This method can be called from any thread.
 + (BOOL)hasPendingViewRegistrations;
 
++ (void)registerCrossProcessNotifier;
+
 // This method must be called _AFTER_ registerThreadInteractionsDatabaseView.
 + (void)registerThreadDatabaseView;
 
diff --git a/SignalServiceKit/src/Storage/TSDatabaseView.m b/SignalServiceKit/src/Storage/TSDatabaseView.m
index 1969b3b233..77f81caf36 100644
--- a/SignalServiceKit/src/Storage/TSDatabaseView.m
+++ b/SignalServiceKit/src/Storage/TSDatabaseView.m
@@ -11,6 +11,7 @@
 #import "TSOutgoingMessage.h"
 #import "TSStorageManager.h"
 #import "TSThread.h"
+#import <YapDatabase/YapDatabaseCrossProcessNotification.h>
 #import <YapDatabase/YapDatabaseView.h>
 
 NSString *const kNSNotificationName_DatabaseViewRegistrationComplete =
@@ -88,6 +89,15 @@ NSString *const TSSecondaryDevicesDatabaseViewExtensionName = @"TSSecondaryDevic
     }
 }
 
++ (void)registerCrossProcessNotifier
+{
+    // I don't think the identifier and name of this extension matter for our purposes,
+    // so long as they don't conflict with any other extension names.
+    YapDatabaseExtension *extension =
+        [[YapDatabaseCrossProcessNotification alloc] initWithIdentifier:@"SignalCrossProcessNotifier"];
+    [[TSStorageManager sharedManager].database registerExtension:extension withName:@"SignalCrossProcessNotifier"];
+}
+
 + (void)registerMessageDatabaseViewWithName:(NSString *)viewName
                                viewGrouping:(YapDatabaseViewGrouping *)viewGrouping
                                     version:(NSString *)version
diff --git a/SignalServiceKit/src/Storage/TSStorageManager.m b/SignalServiceKit/src/Storage/TSStorageManager.m
index 57ae4d62f2..b1877cb59b 100644
--- a/SignalServiceKit/src/Storage/TSStorageManager.m
+++ b/SignalServiceKit/src/Storage/TSStorageManager.m
@@ -310,6 +310,7 @@ void setDatabaseInitialized()
 - (void)setupDatabaseWithSafeBlockingMigrations:(void (^_Nonnull)())safeBlockingMigrationsBlock
 {
     // Synchronously register extensions which are essential for views.
+    [TSDatabaseView registerCrossProcessNotifier];
     [TSDatabaseView registerThreadInteractionsDatabaseView];
     [TSDatabaseView registerThreadDatabaseView];
     [TSDatabaseView registerUnreadDatabaseView];