diff --git a/program/lib/Roundcube/rcube_db.php b/program/lib/Roundcube/rcube_db.php
index 597fa75f9..fe5ed39c5 100644
--- a/program/lib/Roundcube/rcube_db.php
+++ b/program/lib/Roundcube/rcube_db.php
@@ -100,27 +100,15 @@ class rcube_db
 
         $this->db_dsnw_array = self::parse_dsn($db_dsnw);
         $this->db_dsnr_array = self::parse_dsn($db_dsnr);
-
-        // Initialize driver class
-        $this->init();
-    }
-
-    /**
-     * Initialization of the object with driver specific code
-     */
-    protected function init()
-    {
-        // To be used by driver classes
     }
 
     /**
      * Connect to specific database
      *
-     * @param array $dsn DSN for DB connections
-     *
-     * @return PDO database handle
+     * @param array  $dsn  DSN for DB connections
+     * @param string $mode Connection mode (r|w)
      */
-    protected function dsn_connect($dsn)
+    protected function dsn_connect($dsn, $mode)
     {
         $this->db_error     = false;
         $this->db_error_msg = null;
@@ -158,9 +146,10 @@ class rcube_db
             return null;
         }
 
+        $this->dbh          = $dbh;
+        $this->db_mode      = $mode;
+        $this->db_connected = true;
         $this->conn_configure($dsn, $dbh);
-
-        return $dbh;
     }
 
     /**
@@ -182,16 +171,6 @@ class rcube_db
     {
     }
 
-    /**
-     * Driver-specific database character set setting
-     *
-     * @param string $charset Character set name
-     */
-    protected function set_charset($charset)
-    {
-        $this->query("SET NAMES 'utf8'");
-    }
-
     /**
      * Connect to appropriate database depending on the operation
      *
@@ -219,23 +198,14 @@ class rcube_db
 
         $dsn = ($mode == 'r') ? $this->db_dsnr_array : $this->db_dsnw_array;
 
-        $this->dbh          = $this->dsn_connect($dsn);
-        $this->db_connected = is_object($this->dbh);
+        $this->dsn_connect($dsn, $mode);
 
         // use write-master when read-only fails
         if (!$this->db_connected && $mode == 'r' && $this->is_replicated()) {
-            $mode = 'w';
-            $this->dbh          = $this->dsn_connect($this->db_dsnw_array);
-            $this->db_connected = is_object($this->dbh);
+            $this->dsn_connect($this->db_dsnw_array, 'w');
         }
 
-        if ($this->db_connected) {
-            $this->db_mode = $mode;
-            $this->set_charset('utf8');
-        }
-        else {
-            $this->conn_failure = true;
-        }
+        $this->conn_failure = !$this->db_connected;
     }
 
     /**
diff --git a/program/lib/Roundcube/rcube_db_mssql.php b/program/lib/Roundcube/rcube_db_mssql.php
index 4c005b0d0..3c1b9d71f 100644
--- a/program/lib/Roundcube/rcube_db_mssql.php
+++ b/program/lib/Roundcube/rcube_db_mssql.php
@@ -29,22 +29,20 @@ class rcube_db_mssql extends rcube_db
     public $db_provider = 'mssql';
 
     /**
-     * Driver initialization
+     * Object constructor
+     *
+     * @param string $db_dsnw DSN for read/write operations
+     * @param string $db_dsnr Optional DSN for read only operations
+     * @param bool   $pconn   Enables persistent connections
      */
-    protected function init()
+    public function __construct($db_dsnw, $db_dsnr = '', $pconn = false)
     {
+        parent::__construct($db_dsnw, $db_dsnr, $pconn);
+
         $this->options['identifier_start'] = '[';
         $this->options['identifier_end'] = ']';
     }
 
-    /**
-     * Character setting
-     */
-    protected function set_charset($charset)
-    {
-        // UTF-8 is default
-    }
-
     /**
      * Driver-specific configuration of database connection
      *
diff --git a/program/lib/Roundcube/rcube_db_mysql.php b/program/lib/Roundcube/rcube_db_mysql.php
index 2d42610b6..6fa5ad768 100644
--- a/program/lib/Roundcube/rcube_db_mysql.php
+++ b/program/lib/Roundcube/rcube_db_mysql.php
@@ -30,9 +30,13 @@ class rcube_db_mysql extends rcube_db
     public $db_provider = 'mysql';
 
     /**
-     * Driver initialization/configuration
+     * Object constructor
+     *
+     * @param string $db_dsnw DSN for read/write operations
+     * @param string $db_dsnr Optional DSN for read only operations
+     * @param bool   $pconn   Enables persistent connections
      */
-    protected function init()
+    public function __construct($db_dsnw, $db_dsnr = '', $pconn = false)
     {
         if (version_compare(PHP_VERSION, '5.3.0', '<')) {
             rcube::raise_error(array('code' => 600, 'type' => 'db',
@@ -41,11 +45,24 @@ class rcube_db_mysql extends rcube_db
                 true, true);
         }
 
+        parent::__construct($db_dsnw, $db_dsnr, $pconn);
+
         // SQL identifiers quoting
         $this->options['identifier_start'] = '`';
         $this->options['identifier_end'] = '`';
     }
 
+    /**
+     * Driver-specific configuration of database connection
+     *
+     * @param array $dsn DSN for DB connections
+     * @param PDO   $dbh Connection handler
+     */
+    protected function conn_configure($dsn, $dbh)
+    {
+        $this->query("SET NAMES 'utf8'");
+    }
+
     /**
      * Abstract SQL statement for value concatenation
      *
diff --git a/program/lib/Roundcube/rcube_db_pgsql.php b/program/lib/Roundcube/rcube_db_pgsql.php
index 984dd57a1..d72c9d6b3 100644
--- a/program/lib/Roundcube/rcube_db_pgsql.php
+++ b/program/lib/Roundcube/rcube_db_pgsql.php
@@ -28,6 +28,17 @@ class rcube_db_pgsql extends rcube_db
 {
     public $db_provider = 'postgres';
 
+    /**
+     * Driver-specific configuration of database connection
+     *
+     * @param array $dsn DSN for DB connections
+     * @param PDO   $dbh Connection handler
+     */
+    protected function conn_configure($dsn, $dbh)
+    {
+        $this->query("SET NAMES 'utf8'");
+    }
+
     /**
      * Get last inserted record ID
      *
diff --git a/program/lib/Roundcube/rcube_db_sqlite.php b/program/lib/Roundcube/rcube_db_sqlite.php
index cef6621c2..b66c56097 100644
--- a/program/lib/Roundcube/rcube_db_sqlite.php
+++ b/program/lib/Roundcube/rcube_db_sqlite.php
@@ -28,13 +28,6 @@ class rcube_db_sqlite extends rcube_db
 {
     public $db_provider = 'sqlite';
 
-    /**
-     * Database character set
-     */
-    protected function set_charset($charset)
-    {
-    }
-
     /**
      * Prepare connection
      */
diff --git a/program/lib/Roundcube/rcube_db_sqlsrv.php b/program/lib/Roundcube/rcube_db_sqlsrv.php
index 88473e213..45c41cdaf 100644
--- a/program/lib/Roundcube/rcube_db_sqlsrv.php
+++ b/program/lib/Roundcube/rcube_db_sqlsrv.php
@@ -29,22 +29,20 @@ class rcube_db_sqlsrv extends rcube_db
     public $db_provider = 'mssql';
 
     /**
-     * Driver initialization
+     * Object constructor
+     *
+     * @param string $db_dsnw DSN for read/write operations
+     * @param string $db_dsnr Optional DSN for read only operations
+     * @param bool   $pconn   Enables persistent connections
      */
-    protected function init()
+    public function __construct($db_dsnw, $db_dsnr = '', $pconn = false)
     {
+        parent::__construct($db_dsnw, $db_dsnr, $pconn);
+
         $this->options['identifier_start'] = '[';
         $this->options['identifier_end'] = ']';
     }
 
-    /**
-     * Database character set setting
-     */
-    protected function set_charset($charset)
-    {
-        // UTF-8 is default
-    }
-
     /**
      * Driver-specific configuration of database connection
      *