diff --git a/SQL/mssql.initial.sql b/SQL/mssql.initial.sql
index b3bb1c8b8..a8d1a0b89 100644
--- a/SQL/mssql.initial.sql
+++ b/SQL/mssql.initial.sql
@@ -210,7 +210,8 @@ CREATE  INDEX [IX_cache_created] ON [dbo].[cache]([created]) ON [PRIMARY]
 GO
 
 ALTER TABLE [dbo].[cache_index] ADD 
-	CONSTRAINT [DF_cache_index_changed] DEFAULT (getdate()) FOR [changed]
+	CONSTRAINT [DF_cache_index_changed] DEFAULT (getdate()) FOR [changed],
+	CONSTRAINT [DF_cache_index_valid] DEFAULT ('0') FOR [valid]
 GO
 
 CREATE  INDEX [IX_cache_index_user_id] ON [dbo].[cache_index]([user_id]) ON [PRIMARY]
@@ -224,7 +225,7 @@ CREATE  INDEX [IX_cache_thread_user_id] ON [dbo].[cache_thread]([user_id]) ON [P
 GO
 
 ALTER TABLE [dbo].[cache_messages] ADD 
-	CONSTRAINT [DF_cache_messages_changed] DEFAULT (getdate()) FOR [changed]
+	CONSTRAINT [DF_cache_messages_changed] DEFAULT (getdate()) FOR [changed],
 	CONSTRAINT [DF_cache_messages_flags] DEFAULT (0) FOR [flags],
 GO
 
diff --git a/SQL/mssql.upgrade.sql b/SQL/mssql.upgrade.sql
index 3def890bd..b506e5d96 100644
--- a/SQL/mssql.upgrade.sql
+++ b/SQL/mssql.upgrade.sql
@@ -157,6 +157,7 @@ CREATE TABLE [dbo].[cache_index] (
 	[user_id] [int] NOT NULL ,
 	[mailbox] [varchar] (128) COLLATE Latin1_General_CI_AI NOT NULL ,
 	[changed] [datetime] NOT NULL ,
+	[valid] [char] (1) COLLATE Latin1_General_CI_AI NOT NULL ,
 	[data] [text] COLLATE Latin1_General_CI_AI NOT NULL 
 ) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
 GO
@@ -201,7 +202,8 @@ ALTER TABLE [dbo].[cache_messages] WITH NOCHECK ADD
 GO
 
 ALTER TABLE [dbo].[cache_index] ADD 
-	CONSTRAINT [DF_cache_index_changed] DEFAULT (getdate()) FOR [changed]
+	CONSTRAINT [DF_cache_index_changed] DEFAULT (getdate()) FOR [changed],
+	CONSTRAINT [DF_cache_index_valid] DEFAULT ('0') FOR [valid]
 GO
 
 CREATE  INDEX [IX_cache_index_user_id] ON [dbo].[cache_index]([user_id]) ON [PRIMARY]
diff --git a/SQL/mysql.update.sql b/SQL/mysql.update.sql
index 7e8f98f03..6181622e7 100644
--- a/SQL/mysql.update.sql
+++ b/SQL/mysql.update.sql
@@ -177,6 +177,7 @@ CREATE TABLE `cache_index` (
  `user_id` int(10) UNSIGNED NOT NULL DEFAULT '0',
  `mailbox` varchar(255) BINARY NOT NULL,
  `changed` datetime NOT NULL DEFAULT '1000-01-01 00:00:00',
+ `valid` tinyint(1) NOT NULL DEFAULT '0',
  `data` longtext NOT NULL,
  CONSTRAINT `user_id_fk_cache_index` FOREIGN KEY (`user_id`)
    REFERENCES `users`(`user_id`) ON DELETE CASCADE ON UPDATE CASCADE,
diff --git a/SQL/postgres.update.sql b/SQL/postgres.update.sql
index 741495fbe..7e650af7a 100644
--- a/SQL/postgres.update.sql
+++ b/SQL/postgres.update.sql
@@ -135,6 +135,7 @@ CREATE TABLE cache_index (
     	REFERENCES users (user_id) ON DELETE CASCADE ON UPDATE CASCADE,
     mailbox varchar(255) NOT NULL,
     changed timestamp with time zone DEFAULT now() NOT NULL,
+    valid smallint NOT NULL DEFAULT 0,
     data text NOT NULL,
     PRIMARY KEY (user_id, mailbox)
 );
diff --git a/SQL/sqlite.update.sql b/SQL/sqlite.update.sql
index 6f009754e..f7fd168af 100644
--- a/SQL/sqlite.update.sql
+++ b/SQL/sqlite.update.sql
@@ -254,6 +254,7 @@ CREATE TABLE cache_index (
     user_id integer NOT NULL,
     mailbox varchar(255) NOT NULL,
     changed datetime NOT NULL default '0000-00-00 00:00:00',
+    valid smallint NOT NULL DEFAULT '0',
     data text NOT NULL,
     PRIMARY KEY (user_id, mailbox)
 );