diff --git a/INSTALL b/INSTALL
index 16a97ebf7..eac85e73b 100644
--- a/INSTALL
+++ b/INSTALL
@@ -28,7 +28,8 @@ REQUIREMENTS
    - suhosin.session.encrypt disabled
    - mbstring.func_overload disabled
 * PHP compiled with OpenSSL to connect to IMAPS and to use the spell checker
-* A MySQL, PostgreSQL or MSSQL database engine or the SQLite extension for PHP
+* A MySQL (4.0.8 or newer), PostgreSQL, MSSQL database engine
+  or the SQLite extension for PHP
 * One of the above databases with permission to create tables
 * An SMTP server (recommended) or PHP configured for mail delivery
 
diff --git a/SQL/mysql.initial.sql b/SQL/mysql.initial.sql
index 25d11b50f..7a22a60f6 100644
--- a/SQL/mysql.initial.sql
+++ b/SQL/mysql.initial.sql
@@ -52,15 +52,13 @@ CREATE TABLE `messages` (
  `headers` text NOT NULL,
  `structure` text,
  PRIMARY KEY(`message_id`),
+ CONSTRAINT `user_id_fk_messages` FOREIGN KEY (`user_id`)
+   REFERENCES `users`(`user_id`) ON DELETE CASCADE ON UPDATE CASCADE,
  INDEX `created_index` (`created`),
  INDEX `index_index` (`user_id`, `cache_key`, `idx`),
  UNIQUE `uniqueness` (`user_id`, `cache_key`, `uid`)
 ) /*!40000 ENGINE=INNODB */ /*!40101 CHARACTER SET utf8 COLLATE utf8_general_ci */;
 
-/* create foreign keys outside of create table, because of MySQL bug #46293 */
-ALTER TABLE `messages` ADD CONSTRAINT `user_id_fk_messages` FOREIGN KEY (`user_id`)
- REFERENCES `users`(`user_id`) /*!40008 ON DELETE CASCADE ON UPDATE CASCADE */;
-
 
 -- Table structure for table `cache`
 
@@ -71,14 +69,12 @@ CREATE TABLE `cache` (
  `data` longtext NOT NULL,
  `user_id` int(10) UNSIGNED NOT NULL DEFAULT '0',
  PRIMARY KEY(`cache_id`),
+ CONSTRAINT `user_id_fk_cache` FOREIGN KEY (`user_id`)
+   REFERENCES `users`(`user_id`) ON DELETE CASCADE ON UPDATE CASCADE,
  INDEX `created_index` (`created`),
  INDEX `user_cache_index` (`user_id`,`cache_key`)
 ) /*!40000 ENGINE=INNODB */ /*!40101 CHARACTER SET utf8 COLLATE utf8_general_ci */;
 
-/* create foreign keys outside of create table, because of MySQL bug #46293 */
-ALTER TABLE `cache` ADD CONSTRAINT `user_id_fk_cache` FOREIGN KEY (`user_id`)
- REFERENCES `users`(`user_id`) /*!40008 ON DELETE CASCADE ON UPDATE CASCADE */;
-
 
 -- Table structure for table `contacts`
 
@@ -93,13 +89,11 @@ CREATE TABLE `contacts` (
  `vcard` text NULL,
  `user_id` int(10) UNSIGNED NOT NULL DEFAULT '0',
  PRIMARY KEY(`contact_id`),
+ CONSTRAINT `user_id_fk_contacts` FOREIGN KEY (`user_id`)
+   REFERENCES `users`(`user_id`) ON DELETE CASCADE ON UPDATE CASCADE,
  INDEX `user_contacts_index` (`user_id`,`email`)
 ) /*!40000 ENGINE=INNODB */ /*!40101 CHARACTER SET utf8 COLLATE utf8_general_ci */;
 
-/* create foreign keys outside of create table, because of MySQL bug #46293 */
-ALTER TABLE `contacts` ADD CONSTRAINT `user_id_fk_contacts` FOREIGN KEY (`user_id`)
- REFERENCES `users`(`user_id`) /*!40008 ON DELETE CASCADE ON UPDATE CASCADE */;
-
 
 -- Table structure for table `identities`
 
@@ -115,12 +109,11 @@ CREATE TABLE `identities` (
  `signature` text,
  `html_signature` tinyint(1) NOT NULL DEFAULT '0',
  `user_id` int(10) UNSIGNED NOT NULL DEFAULT '0',
- PRIMARY KEY(`identity_id`)
+ PRIMARY KEY(`identity_id`),
+ CONSTRAINT `user_id_fk_identities` FOREIGN KEY (`user_id`)
+   REFERENCES `users`(`user_id`) ON DELETE CASCADE ON UPDATE CASCADE,
+ INDEX `user_identities_index` (`user_id`, `del`)
 ) /*!40000 ENGINE=INNODB */ /*!40101 CHARACTER SET utf8 COLLATE utf8_general_ci */;
 
-/* create foreign keys outside of create table, because of MySQL bug #46293 */
-ALTER TABLE `identities` ADD CONSTRAINT `user_id_fk_identities` FOREIGN KEY (`user_id`)
- REFERENCES `users`(`user_id`) /*!40008 ON DELETE CASCADE ON UPDATE CASCADE */;
-
 
 /*!40014 SET FOREIGN_KEY_CHECKS=1 */;
diff --git a/SQL/mysql.update.sql b/SQL/mysql.update.sql
index 495b600ed..8d86867ce 100644
--- a/SQL/mysql.update.sql
+++ b/SQL/mysql.update.sql
@@ -69,16 +69,18 @@ ALTER TABLE `contacts` DROP FOREIGN KEY `user_id_fk_contacts`;
 ALTER TABLE `identities` DROP FOREIGN KEY `user_id_fk_identities`;
 
 ALTER TABLE `messages` ADD CONSTRAINT `user_id_fk_messages` FOREIGN KEY (`user_id`)
- REFERENCES `users`(`user_id`) /*!40008 ON DELETE CASCADE ON UPDATE CASCADE */;
+ REFERENCES `users`(`user_id`);
 ALTER TABLE `cache` ADD CONSTRAINT `user_id_fk_cache` FOREIGN KEY (`user_id`)
- REFERENCES `users`(`user_id`) /*!40008 ON DELETE CASCADE ON UPDATE CASCADE */;
+ REFERENCES `users`(`user_id`);
 ALTER TABLE `contacts` ADD CONSTRAINT `user_id_fk_contacts` FOREIGN KEY (`user_id`)
- REFERENCES `users`(`user_id`) /*!40008 ON DELETE CASCADE ON UPDATE CASCADE */;
+ REFERENCES `users`(`user_id`);
 ALTER TABLE `identities` ADD CONSTRAINT `user_id_fk_identities` FOREIGN KEY (`user_id`)
- REFERENCES `users`(`user_id`) /*!40008 ON DELETE CASCADE ON UPDATE CASCADE */;
+ REFERENCES `users`(`user_id`);
 
 ALTER TABLE `contacts` ALTER `name` SET DEFAULT '';
 ALTER TABLE `contacts` ALTER `firstname` SET DEFAULT '';
 ALTER TABLE `contacts` ALTER `surname` SET DEFAULT '';
 
+ALTER TABLE `identities` INDEX `user_identities_index` (`user_id`, `del`);
+
 /*!40014 SET FOREIGN_KEY_CHECKS=1 */;
diff --git a/SQL/postgres.initial.sql b/SQL/postgres.initial.sql
index a52a01f91..c634b4b3b 100644
--- a/SQL/postgres.initial.sql
+++ b/SQL/postgres.initial.sql
@@ -78,7 +78,7 @@ CREATE TABLE identities (
     html_signature integer DEFAULT 0 NOT NULL
 );
 
-CREATE INDEX identities_user_id_idx ON identities (user_id);
+CREATE INDEX identities_user_id_idx ON identities (user_id, del);
 
 
 --
diff --git a/SQL/postgres.update.sql b/SQL/postgres.update.sql
index cb83f511b..0b926d5e1 100644
--- a/SQL/postgres.update.sql
+++ b/SQL/postgres.update.sql
@@ -43,3 +43,8 @@ TRUNCATE messages;
 CREATE INDEX messages_index_idx ON messages (user_id, cache_key, idx);
 DROP INDEX contacts_user_id_idx;
 CREATE INDEX contacts_user_id_idx ON contacts (user_id, email);
+
+-- Updates from version 0.3.1
+
+DROP INDEX identities_user_id_idx;
+CREATE INDEX identities_user_id_idx ON identities (user_id, del);
diff --git a/SQL/sqlite.initial.sql b/SQL/sqlite.initial.sql
index cccad7a20..30546bbb2 100644
--- a/SQL/sqlite.initial.sql
+++ b/SQL/sqlite.initial.sql
@@ -56,7 +56,7 @@ CREATE TABLE identities (
   html_signature tinyint NOT NULL default '0'
 );
 
-CREATE INDEX ix_identities_user_id ON identities(user_id);
+CREATE INDEX ix_identities_user_id ON identities(user_id, del);
 
 
 -- --------------------------------------------------------
diff --git a/SQL/sqlite.update.sql b/SQL/sqlite.update.sql
index 329e1911c..fd90d48f6 100644
--- a/SQL/sqlite.update.sql
+++ b/SQL/sqlite.update.sql
@@ -22,7 +22,6 @@ CREATE TABLE messages (
 );
 
 CREATE INDEX ix_messages_user_cache_uid ON messages(user_id,cache_key,uid);
-
 CREATE INDEX ix_users_username ON users(username);
 CREATE INDEX ix_users_alias ON users(alias);
 
@@ -43,3 +42,8 @@ CREATE UNIQUE INDEX ix_messages_user_cache_uid ON messages (user_id,cache_key,ui
 CREATE INDEX ix_messages_index ON messages (user_id,cache_key,idx);
 DROP INDEX ix_contacts_user_id;
 CREATE INDEX ix_contacts_user_id ON contacts(user_id, email);
+
+-- Updates from version 0.3.1
+
+DROP INDEX ix_identities_user_id;
+CREATE INDEX ix_identities_user_id ON identities (user_id, del);