Index: branches/5.2.x/core/install/upgrades.sql
===================================================================
diff -u -N -r15246 -r15253
--- branches/5.2.x/core/install/upgrades.sql	(.../upgrades.sql)	(revision 15246)
+++ branches/5.2.x/core/install/upgrades.sql	(.../upgrades.sql)	(revision 15253)
@@ -2709,3 +2709,18 @@
 UPDATE CachedUrls
 SET Hash = CAST((Hash & 0xFFFFFFFF) AS UNSIGNED INTEGER)
 WHERE Hash < 0;
+
+ALTER TABLE EmailEvents ADD BindToSystemEvent VARCHAR(255) NOT NULL DEFAULT '';
+
+CREATE TABLE EmailEventSubscribers (
+  SubscriptionId int(11) NOT NULL AUTO_INCREMENT,
+  EmailEventId int(11) DEFAULT NULL,
+  SubscriberEmail varchar(255) NOT NULL DEFAULT '',
+  UserId int(11) DEFAULT NULL,
+  CategoryId int(11) DEFAULT NULL,
+  ItemId int(11) DEFAULT NULL,
+  ParentItemId int(11) DEFAULT NULL,
+  SubscribedOn int(11) DEFAULT NULL,
+  PRIMARY KEY (SubscriptionId),
+  KEY EmailEventId (EmailEventId)
+);
