diff --git a/CHANGELOG b/CHANGELOG
index 713f84bca..17f4ed2a6 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,6 +1,10 @@
 CHANGELOG Roundcube Webmail
 ===========================
 
+- Automatically collected recipients and trusted senders (#6904)
+    - Added configurable Collected Recipients addressbook source (#4971)
+    - Added configurable Trusted Senders addressbook source (#5046)
+    - Added 'contact_exists' hook
 - OAuth/XOauth support (#7425, #6933)
 - Cache refactoring (#6312)
 - Added special value 'email' to login_username_filter, it changes also logon input type (#7179)
diff --git a/SQL/mssql.initial.sql b/SQL/mssql.initial.sql
index 72857dc36..4515ca41d 100644
--- a/SQL/mssql.initial.sql
+++ b/SQL/mssql.initial.sql
@@ -40,6 +40,16 @@ CREATE TABLE [dbo].[cache_messages] (
 ) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
 GO
 
+CREATE TABLE [dbo].[collected_addresses] (
+	[address_id] [int] IDENTITY (1, 1) NOT NULL ,
+	[user_id] [int] NOT NULL ,
+	[changed] [datetime] NOT NULL ,
+	[name] [varchar] (255) COLLATE Latin1_General_CI_AI NOT NULL ,
+	[email] [varchar] (255) COLLATE Latin1_General_CI_AI NOT NULL ,
+	[type] [int] NOT NULL 
+) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
+GO
+
 CREATE TABLE [dbo].[contacts] (
 	[contact_id] [int] IDENTITY (1, 1) NOT NULL ,
 	[user_id] [int] NOT NULL ,
@@ -174,6 +184,13 @@ ALTER TABLE [dbo].[cache_messages] WITH NOCHECK ADD
 	) ON [PRIMARY] 
 GO
 
+ALTER TABLE [dbo].[collected_addresses] WITH NOCHECK ADD 
+	CONSTRAINT [PK_collected_addresses_addres_id] PRIMARY KEY  CLUSTERED 
+	(
+		[address_id]
+	) ON [PRIMARY] 
+GO
+
 ALTER TABLE [dbo].[contacts] WITH NOCHECK ADD 
 	CONSTRAINT [PK_contacts_contact_id] PRIMARY KEY  CLUSTERED 
 	(
@@ -277,6 +294,15 @@ GO
 CREATE INDEX [IX_cache_messages_expires] ON [dbo].[cache_messages]([expires]) ON [PRIMARY]
 GO
 
+ALTER TABLE [dbo].[collected_addresses] ADD 
+	CONSTRAINT [DF_collected_addresses_user_id] DEFAULT (0) FOR [user_id],
+	CONSTRAINT [DF_collected_addresses_changed] DEFAULT (getdate()) FOR [changed],
+	CONSTRAINT [DF_collected_addresses_name] DEFAULT ('') FOR [name],
+GO
+
+CREATE UNIQUE INDEX [IX_collected_addresses_user_id] ON [dbo].[collected_addresses]([user_id],[type],[email]) ON [PRIMARY]
+GO
+
 ALTER TABLE [dbo].[contacts] ADD 
 	CONSTRAINT [DF_contacts_user_id] DEFAULT (0) FOR [user_id],
 	CONSTRAINT [DF_contacts_changed] DEFAULT (getdate()) FOR [changed],
@@ -369,6 +395,11 @@ ALTER TABLE [dbo].[identities] ADD CONSTRAINT [FK_identities_user_id]
     ON DELETE CASCADE ON UPDATE CASCADE
 GO
 
+ALTER TABLE [dbo].[collected_addresses] ADD CONSTRAINT [FK_collected_addresses_user_id]
+    FOREIGN KEY ([user_id]) REFERENCES [dbo].[users] ([user_id])
+    ON DELETE CASCADE ON UPDATE CASCADE
+GO
+
 ALTER TABLE [dbo].[contacts] ADD CONSTRAINT [FK_contacts_user_id]
     FOREIGN KEY ([user_id]) REFERENCES [dbo].[users] ([user_id])
     ON DELETE CASCADE ON UPDATE CASCADE
@@ -422,6 +453,6 @@ CREATE TRIGGER [contact_delete_member] ON [dbo].[contacts]
     WHERE [contact_id] IN (SELECT [contact_id] FROM deleted)
 GO
 
-INSERT INTO [dbo].[system] ([name], [value]) VALUES ('roundcube-version', '2020020101')
+INSERT INTO [dbo].[system] ([name], [value]) VALUES ('roundcube-version', '2020091000')
 GO
 
\ No newline at end of file
diff --git a/SQL/mssql/2020091000.sql b/SQL/mssql/2020091000.sql
new file mode 100644
index 000000000..2f79b5287
--- /dev/null
+++ b/SQL/mssql/2020091000.sql
@@ -0,0 +1,31 @@
+CREATE TABLE [dbo].[collected_addresses] (
+	[address_id] [int] IDENTITY (1, 1) NOT NULL ,
+	[user_id] [int] NOT NULL ,
+	[changed] [datetime] NOT NULL ,
+	[name] [varchar] (255) COLLATE Latin1_General_CI_AI NOT NULL ,
+	[email] [varchar] (255) COLLATE Latin1_General_CI_AI NOT NULL ,
+	[type] [int] NOT NULL 
+) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
+GO
+
+ALTER TABLE [dbo].[collected_addresses] WITH NOCHECK ADD 
+	CONSTRAINT [PK_collected_addresses_addres_id] PRIMARY KEY  CLUSTERED 
+	(
+		[address_id]
+	) ON [PRIMARY] 
+GO
+
+ALTER TABLE [dbo].[collected_addresses] ADD 
+	CONSTRAINT [DF_collected_addresses_user_id] DEFAULT (0) FOR [user_id],
+	CONSTRAINT [DF_collected_addresses_changed] DEFAULT (getdate()) FOR [changed],
+	CONSTRAINT [DF_collected_addresses_name] DEFAULT ('') FOR [name],
+GO
+
+CREATE UNIQUE INDEX [IX_collected_addresses_user_id] ON [dbo].[collected_addresses]([user_id],[type],[email]) ON [PRIMARY]
+GO
+
+ALTER TABLE [dbo].[collected_addresses] ADD CONSTRAINT [FK_collected_addresses_user_id]
+    FOREIGN KEY ([user_id]) REFERENCES [dbo].[users] ([user_id])
+    ON DELETE CASCADE ON UPDATE CASCADE
+GO
+
diff --git a/SQL/mysql.initial.sql b/SQL/mysql.initial.sql
index 8981e0c3b..2d308a1ba 100644
--- a/SQL/mysql.initial.sql
+++ b/SQL/mysql.initial.sql
@@ -102,6 +102,22 @@ CREATE TABLE `cache_messages` (
 ) /*!40000 ENGINE=INNODB */ /*!40101 CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci */;
 
 
+-- Table structure for table `collected_addresses`
+
+CREATE TABLE `collected_addresses` (
+ `address_id` int(10) UNSIGNED NOT NULL AUTO_INCREMENT,
+ `changed` datetime NOT NULL DEFAULT '1000-01-01 00:00:00',
+ `name` varchar(255) NOT NULL DEFAULT '',
+ `email` varchar(255) NOT NULL,
+ `user_id` int(10) UNSIGNED NOT NULL,
+ `type` int(10) UNSIGNED NOT NULL,
+ PRIMARY KEY(`address_id`),
+ CONSTRAINT `user_id_fk_collected_addresses` FOREIGN KEY (`user_id`)
+   REFERENCES `users`(`user_id`) ON DELETE CASCADE ON UPDATE CASCADE,
+ UNIQUE INDEX `user_email_collected_addresses_index` (`user_id`, `type`, `email`)
+) /*!40000 ENGINE=INNODB */ /*!40101 CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci */;
+
+
 -- Table structure for table `contacts`
 
 CREATE TABLE `contacts` (
@@ -121,6 +137,7 @@ CREATE TABLE `contacts` (
  INDEX `user_contacts_index` (`user_id`,`del`)
 ) /*!40000 ENGINE=INNODB */ /*!40101 CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci */;
 
+
 -- Table structure for table `contactgroups`
 
 CREATE TABLE `contactgroups` (
@@ -135,6 +152,9 @@ CREATE TABLE `contactgroups` (
   INDEX `contactgroups_user_index` (`user_id`,`del`)
 ) /*!40000 ENGINE=INNODB */ /*!40101 CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci */;
 
+
+-- Table structure for table `contactgroupmembers`
+
 CREATE TABLE `contactgroupmembers` (
   `contactgroup_id` int(10) UNSIGNED NOT NULL,
   `contact_id` int(10) UNSIGNED NOT NULL,
@@ -223,4 +243,4 @@ CREATE TABLE `system` (
 
 /*!40014 SET FOREIGN_KEY_CHECKS=1 */;
 
-INSERT INTO `system` (`name`, `value`) VALUES ('roundcube-version', '2020020101');
+INSERT INTO `system` (`name`, `value`) VALUES ('roundcube-version', '2020091000');
diff --git a/SQL/mysql/2020091000.sql b/SQL/mysql/2020091000.sql
new file mode 100644
index 000000000..cc91fe0f2
--- /dev/null
+++ b/SQL/mysql/2020091000.sql
@@ -0,0 +1,12 @@
+CREATE TABLE `collected_addresses` (
+ `address_id` int(10) UNSIGNED NOT NULL AUTO_INCREMENT,
+ `changed` datetime NOT NULL DEFAULT '1000-01-01 00:00:00',
+ `name` varchar(255) NOT NULL DEFAULT '',
+ `email` varchar(255) NOT NULL,
+ `user_id` int(10) UNSIGNED NOT NULL,
+ `type` int(10) UNSIGNED NOT NULL,
+ PRIMARY KEY(`address_id`),
+ CONSTRAINT `user_id_fk_collected_addresses` FOREIGN KEY (`user_id`)
+   REFERENCES `users`(`user_id`) ON DELETE CASCADE ON UPDATE CASCADE,
+ UNIQUE INDEX `user_email_collected_addresses_index` (`user_id`, `type`, `email`)
+) /*!40000 ENGINE=INNODB */ /*!40101 CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci */;
diff --git a/SQL/oracle.initial.sql b/SQL/oracle.initial.sql
index 711e71904..f63b10ff5 100644
--- a/SQL/oracle.initial.sql
+++ b/SQL/oracle.initial.sql
@@ -63,6 +63,28 @@ BEGIN
 END;
 /
 
+CREATE TABLE "collected_addresses" (
+    "address_id" integer PRIMARY KEY,
+    "user_id" integer NOT NULL
+        REFERENCES "users" ("user_id") ON DELETE CASCADE,
+    "changed" timestamp with time zone DEFAULT current_timestamp NOT NULL,
+    "name" varchar(255) DEFAULT NULL,
+    "email" varchar(255) DEFAULT NULL,
+    "type" integer NOT NULL
+);
+
+CREATE UNIQUE INDEX "collected_addresses_user_id_idx" ON "collected_addresses" ("user_id", "type", "email");
+
+CREATE SEQUENCE "collected_addresses_seq"
+    START WITH 1 INCREMENT BY 1 NOMAXVALUE;
+
+CREATE TRIGGER "collected_addresses_seq_trig"
+BEFORE INSERT ON "collected_addresses" FOR EACH ROW
+BEGIN
+    :NEW."address_id" := "collected_addresses_seq".nextval;
+END;
+/
+
 CREATE TABLE "contacts" (
     "contact_id" integer PRIMARY KEY,
     "user_id" integer NOT NULL
@@ -238,4 +260,4 @@ CREATE TABLE "system" (
     "value" long
 );
 
-INSERT INTO "system" ("name", "value") VALUES ('roundcube-version', '2020020101');
+INSERT INTO "system" ("name", "value") VALUES ('roundcube-version', '2020091000');
diff --git a/SQL/oracle/2020091000.sql b/SQL/oracle/2020091000.sql
new file mode 100644
index 000000000..0e598cda6
--- /dev/null
+++ b/SQL/oracle/2020091000.sql
@@ -0,0 +1,21 @@
+CREATE TABLE "collected_addresses" (
+    "address_id" integer PRIMARY KEY,
+    "user_id" integer NOT NULL
+        REFERENCES "users" ("user_id") ON DELETE CASCADE,
+    "changed" timestamp with time zone DEFAULT current_timestamp NOT NULL,
+    "name" varchar(255) DEFAULT NULL,
+    "email" varchar(255) DEFAULT NULL,
+    "type" integer NOT NULL
+);
+
+CREATE UNIQUE INDEX "collected_addresses_user_id_idx" ON "collected_addresses" ("user_id", "type", "email");
+
+CREATE SEQUENCE "collected_addresses_seq"
+    START WITH 1 INCREMENT BY 1 NOMAXVALUE;
+
+CREATE TRIGGER "collected_addresses_seq_trig"
+BEFORE INSERT ON "collected_addresses" FOR EACH ROW
+BEGIN
+    :NEW."address_id" := "collected_addresses_seq".nextval;
+END;
+/
diff --git a/SQL/postgres.initial.sql b/SQL/postgres.initial.sql
index 02be65d98..ab39ad713 100644
--- a/SQL/postgres.initial.sql
+++ b/SQL/postgres.initial.sql
@@ -81,6 +81,35 @@ CREATE TABLE identities (
 CREATE INDEX identities_user_id_idx ON identities (user_id, del);
 CREATE INDEX identities_email_idx ON identities (email, del);
 
+--
+-- Sequence "collected_addresses_seq"
+-- Name: collected_addresses_seq; Type: SEQUENCE; Schema: public; Owner: postgres
+--
+
+CREATE SEQUENCE collected_addresses_seq
+    START WITH 1
+    INCREMENT BY 1
+    NO MAXVALUE
+    NO MINVALUE
+    CACHE 1;
+
+--
+-- Table "collected_addresses"
+-- Name: collected_addresses; Type: TABLE; Schema: public; Owner: postgres
+--
+
+CREATE TABLE collected_addresses (
+    address_id integer DEFAULT nextval('collected_addresses_seq'::text) PRIMARY KEY,
+    user_id integer NOT NULL
+        REFERENCES users (user_id) ON DELETE CASCADE ON UPDATE CASCADE,
+    changed timestamp with time zone DEFAULT now() NOT NULL,
+    name varchar(255) DEFAULT '' NOT NULL,
+    email varchar(255) NOT NULL,
+    "type" integer NOT NULL
+);
+
+CREATE UNIQUE INDEX collected_addresses_user_id_idx ON collected_addresses (user_id, "type", email);
+
 
 --
 -- Sequence "contacts_seq"
@@ -314,4 +343,4 @@ CREATE TABLE "system" (
     value text
 );
 
-INSERT INTO "system" (name, value) VALUES ('roundcube-version', '2020020101');
+INSERT INTO "system" (name, value) VALUES ('roundcube-version', '2020091000');
diff --git a/SQL/postgres/2020091000.sql b/SQL/postgres/2020091000.sql
new file mode 100644
index 000000000..bab9f4eed
--- /dev/null
+++ b/SQL/postgres/2020091000.sql
@@ -0,0 +1,11 @@
+CREATE TABLE collected_addresses (
+    address_id integer DEFAULT nextval('collected_addresses_seq'::text) PRIMARY KEY,
+    user_id integer NOT NULL
+        REFERENCES users (user_id) ON DELETE CASCADE ON UPDATE CASCADE,
+    changed timestamp with time zone DEFAULT now() NOT NULL,
+    name varchar(255) DEFAULT '' NOT NULL,
+    email varchar(255) NOT NULL,
+    "type" integer NOT NULL
+);
+
+CREATE UNIQUE INDEX collected_addresses_user_id_idx ON collected_addresses (user_id, "type", email);
diff --git a/SQL/sqlite.initial.sql b/SQL/sqlite.initial.sql
index 42ab425f1..f9bb845ae 100644
--- a/SQL/sqlite.initial.sql
+++ b/SQL/sqlite.initial.sql
@@ -40,6 +40,21 @@ CREATE TABLE contactgroupmembers (
 
 CREATE INDEX ix_contactgroupmembers_contact_id ON contactgroupmembers (contact_id);
 
+-- 
+-- Table structure for table collected_addresses
+-- 
+
+CREATE TABLE collected_addresses (
+  address_id integer NOT NULL PRIMARY KEY,
+  user_id integer NOT NULL,
+  changed datetime NOT NULL default '0000-00-00 00:00:00',
+  name varchar(255) NOT NULL default '',
+  email varchar(255) NOT NULL,
+  "type" integer NOT NULL
+);
+
+CREATE UNIQUE INDEX ix_collected_addresses_user_id ON collected_addresses(user_id, "type", email);
+
 -- 
 -- Table structure for table identities
 -- 
@@ -215,4 +230,4 @@ CREATE TABLE system (
   value text NOT NULL
 );
 
-INSERT INTO system (name, value) VALUES ('roundcube-version', '2020020101');
+INSERT INTO system (name, value) VALUES ('roundcube-version', '2020091000');
diff --git a/SQL/sqlite/2020091000.sql b/SQL/sqlite/2020091000.sql
new file mode 100644
index 000000000..2ea309629
--- /dev/null
+++ b/SQL/sqlite/2020091000.sql
@@ -0,0 +1,10 @@
+CREATE TABLE collected_addresses (
+  address_id integer NOT NULL PRIMARY KEY,
+  user_id integer NOT NULL,
+  changed datetime NOT NULL default '0000-00-00 00:00:00',
+  name varchar(255) NOT NULL default '',
+  email varchar(255) NOT NULL,
+  "type" integer NOT NULL
+);
+
+CREATE UNIQUE INDEX ix_collected_addresses_user_id ON collected_addresses(user_id, "type", email);
diff --git a/config/defaults.inc.php b/config/defaults.inc.php
index 66bae3fc2..9f4104478 100644
--- a/config/defaults.inc.php
+++ b/config/defaults.inc.php
@@ -1173,6 +1173,17 @@ $config['contactlist_fields'] = array('name', 'firstname', 'surname', 'email');
 // See program/steps/addressbook/func.inc for a list
 $config['contact_search_name'] = '{name} <{email}>';
 
+// The addressbook source to store automatically collected recipients in.
+// Default: true (the build-in "Collected recipients" addressbook, source id = '1')
+// Note: It can be set to any writeable addressbook, e.g. 'sql'
+$config['collected_recipients'] = true;
+
+// The addressbook source to store trusted senders in.
+// Default: true (the build-in "Trusted senders" addressbook, source id = '2')
+// Note: It can be set to any writeable addressbook, e.g. 'sql'
+$config['collected_senders'] = true;
+
+
 // ----------------------------------
 // USER PREFERENCES
 // ----------------------------------
diff --git a/plugins/vcard_attachments/vcard_attachments.php b/plugins/vcard_attachments/vcard_attachments.php
index 458c24272..152e2bb8b 100644
--- a/plugins/vcard_attachments/vcard_attachments.php
+++ b/plugins/vcard_attachments/vcard_attachments.php
@@ -281,10 +281,9 @@ class vcard_attachments extends rcube_plugin
         }
 
         $rcmail = rcmail::get_instance();
-        $abook  = $rcmail->config->get('default_addressbook');
 
         // Get configured addressbook
-        $CONTACTS = $rcmail->get_address_book($abook, true);
+        $CONTACTS = $rcmail->get_address_book(rcube_addressbook::TYPE_DEFAULT, true);
 
         // Get first writeable addressbook if the configured doesn't exist
         // This can happen when user deleted the addressbook (e.g. Kolab folder)
diff --git a/program/include/rcmail.php b/program/include/rcmail.php
index b983f3ac8..89090dbbf 100644
--- a/program/include/rcmail.php
+++ b/program/include/rcmail.php
@@ -208,7 +208,9 @@ class rcmail extends rcube
     /**
      * Return instance of the internal address book class
      *
-     * @param string  $id        Address book identifier (-1 for default addressbook)
+     * @param string  $id        Address book identifier. It accepts also special values:
+     *                           - rcube_addressbook::TYPE_CONTACT (or 'sql') for the SQL addressbook
+     *                           - rcube_addressbook::TYPE_DEFAULT for the default addressbook
      * @param boolean $writeable True if the address book needs to be writeable
      *
      * @return rcube_contacts Address book object
@@ -221,13 +223,15 @@ class rcmail extends rcube
 
         // 'sql' is the alias for '0' used by autocomplete
         if ($id == 'sql') {
-            $id = '0';
+            $id = rcube_addressbook::TYPE_CONTACT;
         }
-        else if ($id == -1) {
+        else if ($id == rcube_addressbook::TYPE_DEFAULT || $id == -1) { // -1 for BC
             $id = $this->config->get('default_addressbook');
             $default = true;
         }
 
+        $id = (string) $id;
+
         // use existing instance
         if (isset($this->address_books[$id]) && ($this->address_books[$id] instanceof rcube_addressbook)) {
             $contacts = $this->address_books[$id];
@@ -236,9 +240,12 @@ class rcmail extends rcube
             $domain   = $this->config->mail_domain($_SESSION['storage_host']);
             $contacts = new rcube_ldap($ldap_config[$id], $this->config->get('ldap_debug'), $domain);
         }
-        else if ($id === '0') {
+        else if ($id === (string) rcube_addressbook::TYPE_CONTACT) {
             $contacts = new rcube_contacts($this->db, $this->get_user_id());
         }
+        else if ($id === (string) rcube_addressbook::TYPE_RECIPIENT || $id === (string) rcube_addressbook::TYPE_TRUSTED_SENDER) {
+            $contacts = new rcube_addresses($this->db, $this->get_user_id(), (int) $id);
+        }
         else {
             $plugin = $this->plugins->exec_hook('addressbook_get', array('id' => $id, 'writeable' => $writeable));
 
@@ -325,22 +332,16 @@ class rcmail extends rcube
     {
         $abook_type   = strtolower((string) $this->config->get('address_book_type', 'sql'));
         $ldap_config  = (array) $this->config->get('ldap_public');
-        $autocomplete = (array) $this->config->get('autocomplete_addressbooks');
         $list         = array();
 
         // SQL-based (built-in) address book
         if ($abook_type === 'sql') {
-            if (!isset($this->address_books['0'])) {
-                $this->address_books['0'] = new rcube_contacts($this->db, $this->get_user_id());
-            }
-
-            $list['0'] = array(
-                'id'       => '0',
+            $list[rcube_addressbook::TYPE_CONTACT] = array(
+                'id'       => (string) rcube_addressbook::TYPE_CONTACT,
                 'name'     => $this->gettext('personaladrbook'),
-                'groups'   => $this->address_books['0']->groups,
-                'readonly' => $this->address_books['0']->readonly,
-                'undelete' => $this->address_books['0']->undelete && $this->config->get('undo_timeout'),
-                'autocomplete' => in_array_nocase('sql', $autocomplete),
+                'groups'   => true,
+                'readonly' => false,
+                'undelete' => $this->config->get('undo_timeout') > 0,
             );
         }
 
@@ -358,20 +359,40 @@ class rcmail extends rcube
                     'groups'   => !empty($prop['groups']) || !empty($prop['group_filters']),
                     'readonly' => !$prop['writable'],
                     'hidden'   => $prop['hidden'],
-                    'autocomplete' => in_array($id, $autocomplete)
                 );
             }
         }
 
+        $collected_recipients = $this->config->get('collected_recipients');
+        $collected_senders    = $this->config->get('collected_senders');
+
+        if ($collected_recipients === (string) rcube_addressbook::TYPE_RECIPIENT) {
+            $list[rcube_addressbook::TYPE_RECIPIENT] = array(
+                'id'       => (string) rcube_addressbook::TYPE_RECIPIENT,
+                'name'     => $this->gettext('collectedrecipients'),
+                'groups'   => false,
+                'readonly' => true,
+                'undelete' => false,
+                'deletable' => true,
+            );
+        }
+
+        if ($collected_senders === (string) rcube_addressbook::TYPE_TRUSTED_SENDER) {
+            $list[rcube_addressbook::TYPE_TRUSTED_SENDER] = array(
+                'id'       => (string) rcube_addressbook::TYPE_TRUSTED_SENDER,
+                'name'     => $this->gettext('trustedsenders'),
+                'groups'   => false,
+                'readonly' => true,
+                'undelete' => false,
+                'deletable' => true,
+            );
+        }
+
         // Plugins can also add address books, or re-order the list
         $plugin = $this->plugins->exec_hook('addressbooks_list', array('sources' => $list));
         $list   = $plugin['sources'];
 
         foreach ($list as $idx => $item) {
-            // register source for shutdown function
-            if (!is_object($this->address_books[$item['id']])) {
-                $this->address_books[$item['id']] = $item;
-            }
             // remove from list if not writeable as requested
             if ($writeable && $item['readonly']) {
                 unset($list[$idx]);
@@ -1169,6 +1190,108 @@ class rcmail extends rcube
         }
     }
 
+    /**
+     * Insert a contact to specified addressbook.
+     *
+     * @param array             $contact Contact data
+     * @param rcube_addressbook $source  The addressbook object
+     * @param string            $error   Filled with an error message/label on error
+     *
+     * @return int|bool Contact ID on success, False otherwise
+     */
+    public function contact_create($contact, $source, &$error = null)
+    {
+        $contact['email'] = rcube_utils::idn_to_utf8($contact['email']);
+
+        $contact = $this->plugins->exec_hook('contact_displayname', $contact);
+
+        if (empty($contact['name'])) {
+            $contact['name'] = rcube_addressbook::compose_display_name($contact);
+        }
+
+        // validate the contact
+        if (!$source->validate($contact, true)) {
+            $error = $source->get_error();
+            return false;
+        }
+
+        $plugin = $this->plugins->exec_hook('contact_create', array(
+                'record' => $contact,
+                'source' => $this->get_address_book_id($source),
+        ));
+
+        $contact = $plugin['record'];
+
+        if (!empty($plugin['abort'])) {
+            $error = $plugin['message'];
+            return $plugin['result'];
+        }
+
+        return $source->insert($contact);
+    }
+
+    /**
+     * Find an email address in user addressbook(s)
+     *
+     * @param string $email Email address
+     * @param int    $type  Addressbook type (see rcube_addressbook::TYPE_* consts)
+     *
+     * @return bool True if the address exists in specified addressbook(s), False otherwise
+     */
+    public function contact_exists($email, $type)
+    {
+        if (empty($email) || !is_string($email) || !strpos($email, '@')) {
+            return false;
+        }
+
+        // TODO: Consider using all writeable addressbooks by default
+        // TODO: Support TYPE_DEFAULT, TYPE_WRITEABLE, TYPE_READONLY filter
+
+        if ($default = $this->get_address_book(rcube_addressbook::TYPE_DEFAULT, true)) {
+            $sources = array($this->get_address_book_id($default));
+        }
+
+        if ($type & rcube_addressbook::TYPE_RECIPIENT) {
+            $collected_recipients = $this->config->get('collected_recipients');
+            if (strlen($collected_recipients) && !in_array($collected_recipients, $sources)) {
+                array_unshift($sources, $collected_recipients);
+            }
+        }
+
+        if ($type & rcube_addressbook::TYPE_TRUSTED_SENDER) {
+            $collected_senders = $this->config->get('collected_senders');
+            if (strlen($collected_senders) && !in_array($collected_senders, $sources)) {
+                array_unshift($sources, $collected_senders);
+            }
+        }
+
+        $plugin = $this->plugins->exec_hook('contact_exists', array(
+                'email'   => $email,
+                'type'    => $type,
+                'sources' => $sources,
+        ));
+
+        if (!empty($plugin['abort'])) {
+            return $plugin['result'];
+        }
+
+        foreach ($plugin['sources'] as $source) {
+            $contacts = $this->get_address_book($source);
+
+            if (!$contacts) {
+                continue;
+            }
+
+            $result = $contacts->search('email', $email, rcube_addressbook::SEARCH_STRICT, false);
+
+            if ($result->count) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
     /**
      * Returns RFC2822 formatted current date in user's timezone
      *
diff --git a/program/include/rcmail_sendmail.php b/program/include/rcmail_sendmail.php
index 6669737c1..2f5801c3a 100644
--- a/program/include/rcmail_sendmail.php
+++ b/program/include/rcmail_sendmail.php
@@ -422,6 +422,9 @@ class rcmail_sendmail
             $this->rcmail->user->save_prefs(array('last_message_time' => time()));
         }
 
+        // Collect recipients' addresses
+        $this->collect_recipients($message);
+
         // set replied/forwarded flag
         if ($this->data['reply_uid']) {
             foreach (rcmail::get_uids($this->data['reply_uid'], $this->data['mailbox']) as $mbox => $uids) {
@@ -1573,4 +1576,54 @@ class rcmail_sendmail
         // default identity is always first on the list
         return $identities[$selected !== null ? $selected : 0];
     }
+
+    /**
+     * Collect message recipients' addresses
+     *
+     * @param Mail_Mime $message The email message
+     */
+    public static function collect_recipients($message)
+    {
+        $rcmail = rcube::get_instance();
+
+        // Find the addressbook source
+        $collected_recipients = $rcmail->config->get('collected_recipients');
+
+        if (!strlen($collected_recipients)) {
+            return;
+        }
+
+        $source = $rcmail->get_address_book($collected_recipients);
+
+        if (!$source) {
+            return;
+        }
+
+        $headers = $message->headers();
+
+        // extract recipients
+        $recipients = (array) $headers['To'];
+
+        if (strlen($headers['Cc'])) {
+            $recipients[] = $headers['Cc'];
+        }
+
+        if (strlen($headers['Bcc'])) {
+            $recipients[] = $headers['Bcc'];
+        }
+
+        $addresses = rcube_mime::decode_address_list($recipients);
+        $type      = rcube_addressbook::TYPE_DEFAULT | rcube_addressbook::TYPE_RECIPIENT;
+
+        foreach ($addresses as $address) {
+            $contact = array(
+                'name'  => $address['name'],
+                'email' => $address['mailto'],
+            );
+
+            if (!$rcmail->contact_exists($contact['email'], $type)) {
+                $rcmail->contact_create($contact, $source);
+            }
+        }
+    }
 }
diff --git a/program/js/app.js b/program/js/app.js
index a7a73f892..8c395e9d4 100644
--- a/program/js/app.js
+++ b/program/js/app.js
@@ -6198,7 +6198,11 @@ function rcube_webmail()
     if (this.preview_timer)
       clearTimeout(this.preview_timer);
 
-    var id, targets, groupcount = 0, writable = false, copy_writable = false,
+    var id, targets,
+      groupcount = 0,
+      writable = false,
+      deletable = false,
+      copy_writable = false,
       selected = list.get_selection().length,
       source = this.env.source ? this.env.address_sources[this.env.source] : null;
 
@@ -6222,16 +6226,20 @@ function rcube_webmail()
       }
 
       $.each(list.get_selection(), function(i, v) {
-        var sid, contact = list.data[v];
+        var book, sid, contact = list.data[v];
         if (!source) {
           sid = String(v).replace(/^[^-]+-/, '');
-          if (sid && ref.env.address_sources[sid]) {
-            writable = writable || (!ref.env.address_sources[sid].readonly && !contact.readonly);
+          book = sid ? ref.env.address_sources[sid] : null;
+
+          if (book) {
+            writable = writable || (!book.readonly && !contact.readonly);
+            deletable = deletable || book.deletable === true;
             ref.env.selection_sources.push(sid);
           }
         }
         else {
           writable = writable || (!source.readonly && !contact.readonly);
+          deletable = deletable || source.deletable === true;
         }
 
         if (contact._type != 'group')
@@ -6254,7 +6262,7 @@ function rcube_webmail()
     this.enable_command('print', 'qrcode', selected == 1);
     this.enable_command('export-selected', selected > 0);
     this.enable_command('edit', id && writable);
-    this.enable_command('delete', 'move', writable);
+    this.enable_command('delete', 'move', writable || deletable);
     this.enable_command('copy', copy_writable);
 
     return false;
@@ -6538,6 +6546,9 @@ function rcube_webmail()
     if (!this.env.address_sources[dest] || this.env.address_sources[dest].readonly)
       return;
 
+    if (!cid)
+      cid = this.contact_list.get_selection();
+
     // search result may contain contacts from many sources, but if there is only one...
     if (source == '' && this.env.selection_sources.length == 1)
       source = this.env.selection_sources[0];
diff --git a/program/lib/Roundcube/rcube_addressbook.php b/program/lib/Roundcube/rcube_addressbook.php
index 2b355d127..9ce5858ea 100644
--- a/program/lib/Roundcube/rcube_addressbook.php
+++ b/program/lib/Roundcube/rcube_addressbook.php
@@ -38,6 +38,14 @@ abstract class rcube_addressbook
     const SEARCH_PREFIX = 2;
     const SEARCH_GROUPS = 4;
 
+    // contact types, note: some of these are used as addressbook source identifiers
+    const TYPE_CONTACT        = 0;
+    const TYPE_RECIPIENT      = 1;
+    const TYPE_TRUSTED_SENDER = 2;
+    const TYPE_DEFAULT        = 4;
+    const TYPE_WRITEABLE      = 8;
+    const TYPE_READONLY       = 16;
+
     // public properties (mandatory)
     public $primary_key;
     public $groups        = false;
diff --git a/program/lib/Roundcube/rcube_addresses.php b/program/lib/Roundcube/rcube_addresses.php
new file mode 100644
index 000000000..3b28f781f
--- /dev/null
+++ b/program/lib/Roundcube/rcube_addresses.php
@@ -0,0 +1,405 @@
+<?php
+
+/**
+ +-----------------------------------------------------------------------+
+ | This file is part of the Roundcube Webmail client                     |
+ |                                                                       |
+ | Copyright (C) The Roundcube Dev Team                                  |
+ |                                                                       |
+ | Licensed under the GNU General Public License version 3 or            |
+ | any later version with exceptions for skins & plugins.                |
+ | See the README file for a full license statement.                     |
+ |                                                                       |
+ | PURPOSE:                                                              |
+ |   Interface to the collected addresses database                       |
+ +-----------------------------------------------------------------------+
+ | Author: Aleksander Machniak <alec@alec.pl>                            |
+ +-----------------------------------------------------------------------+
+*/
+
+/**
+ * Collected addresses database
+ *
+ * @package    Framework
+ * @subpackage Addressbook
+ */
+class rcube_addresses extends rcube_contacts
+{
+    protected $db_name       = 'collected_addresses';
+    protected $type          = 0;
+    protected $table_cols    = array('name', 'email');
+    protected $fulltext_cols = array('name');
+
+    // public properties
+    public $primary_key = 'address_id';
+    public $readonly    = true;
+    public $groups      = false;
+    public $undelete    = false;
+    public $deletable   = true;
+    public $coltypes    = array('name', 'email');
+    public $date_cols   = array();
+
+
+    /**
+     * Object constructor
+     *
+     * @param object  $dbconn Instance of the rcube_db class
+     * @param integer $user   User-ID
+     * @param int     $type   Type of the address (1 - recipient, 2 - trusted sender)
+     */
+    public function __construct($dbconn, $user, $type)
+    {
+        $this->db      = $dbconn;
+        $this->user_id = $user;
+        $this->type    = $type;
+        $this->ready   = $this->db && !$this->db->is_error();
+    }
+
+    /**
+     * Returns addressbook name
+     */
+    public function get_name()
+    {
+        if ($this->type == self::TYPE_RECIPIENT) {
+            return rcube::get_instance()->gettext('collectedrecipients');
+        }
+
+        if ($this->type == self::TYPE_TRUSTED_SENDER) {
+            return rcube::get_instance()->gettext('trustedsenders');
+        }
+
+        return '';
+    }
+
+    /**
+     * List the current set of contact records
+     *
+     * @param  array   List of cols to show, Null means all
+     * @param  int     Only return this number of records, use negative values for tail
+     * @param  boolean True to skip the count query (select only)
+     *
+     * @return array Indexed list of contact records, each a hash array
+     */
+    public function list_records($cols = null, $subset = 0, $nocount = false)
+    {
+        if ($nocount || $this->list_page <= 1) {
+            // create dummy result, we don't need a count now
+            $this->result = new rcube_result_set();
+        } else {
+            // count all records
+            $this->result = $this->count();
+        }
+
+        $start_row  = $subset < 0 ? $this->result->first + $this->page_size + $subset : $this->result->first;
+        $length     = $subset != 0 ? abs($subset) : $this->page_size;
+
+        $sql_result = $this->db->limitquery(
+            "SELECT * FROM " . $this->db->table_name($this->db_name, true)
+            . " WHERE `user_id` = ? AND `type` = ?"
+            . ($this->filter ? " AND ".$this->filter : "")
+            . " ORDER BY `name` " . $this->sort_order . ", `email` " . $this->sort_order,
+            $start_row,
+            $length,
+            $this->user_id,
+            $this->type,
+        );
+
+        while ($sql_result && ($sql_arr = $this->db->fetch_assoc($sql_result))) {
+            $sql_arr['ID'] = $sql_arr[$this->primary_key];
+            $this->result->add($sql_arr);
+        }
+
+        $cnt = count($this->result->records);
+
+        // update counter
+        if ($nocount) {
+            $this->result->count = $cnt;
+        }
+        else if ($this->list_page <= 1) {
+            if ($cnt < $this->page_size && $subset == 0) {
+                $this->result->count = $cnt;
+            }
+            else if (isset($this->cache['count'])) {
+                $this->result->count = $this->cache['count'];
+            }
+            else {
+                $this->result->count = $this->_count();
+            }
+        }
+
+        return $this->result;
+    }
+
+    /**
+     * Search contacts
+     *
+     * @param mixed   $fields   The field name or array of field names to search in
+     * @param mixed   $value    Search value (or array of values when $fields is array)
+     * @param int     $mode     Search mode. Sum of rcube_addressbook::SEARCH_*
+     * @param boolean $select   True if results are requested, False if count only
+     * @param boolean $nocount  True to skip the count query (select only)
+     * @param array   $required List of fields that cannot be empty
+     *
+     * @return object rcube_result_set Contact records and 'count' value
+     */
+    public function search($fields, $value, $mode = 0, $select = true, $nocount = false, $required = array())
+    {
+        if (!is_array($required) && !empty($required)) {
+            $required = array($required);
+        }
+
+        $where = $post_search = array();
+        $mode  = intval($mode);
+
+        // direct ID search
+        if ($fields == 'ID' || $fields == $this->primary_key) {
+            $ids     = !is_array($value) ? explode(self::SEPARATOR, $value) : $value;
+            $ids     = $this->db->array2list($ids, 'integer');
+            $where[] = $this->primary_key . ' IN (' . $ids . ')';
+        }
+        else if (is_array($value)) {
+            foreach ((array) $fields as $idx => $col) {
+                $val = $value[$idx];
+
+                if (!strlen($val)) {
+                    continue;
+                }
+
+                // table column
+                if ($col == 'email' && ($mode & rcube_addressbook::SEARCH_STRICT)) {
+                    $where[] = $this->db->ilike($col, $val);
+                }
+                else if (in_array($col, $this->table_cols)) {
+                    $where[] = $this->fulltext_sql_where($val, $mode, $col);
+                }
+                else {
+                    $where[] = '1 = 0'; // unsupported column
+                }
+            }
+        }
+        else {
+            // fulltext search in all fields
+            if ($fields == '*') {
+                $fields = array('name', 'email');
+            }
+
+            // require each word in to be present in one of the fields
+            $words = ($mode & rcube_addressbook::SEARCH_STRICT) ? array($value) : rcube_utils::tokenize_string($value, 1);
+            foreach ($words as $word) {
+                $groups = array();
+                foreach ((array) $fields as $idx => $col) {
+                    if ($col == 'email' && ($mode & rcube_addressbook::SEARCH_STRICT)) {
+                        $groups[] = $this->db->ilike($col, $word);
+                    }
+                    else if (in_array($col, $this->table_cols)) {
+                        $groups[] = $this->fulltext_sql_where($word, $mode, $col);
+                    }
+                }
+                $where[] = '(' . implode(' OR ', $groups) . ')';
+            }
+        }
+
+        foreach (array_intersect($required, $this->table_cols) as $col) {
+            $where[] = $this->db->quote_identifier($col) . ' <> ' . $this->db->quote('');
+        }
+
+        if (!empty($where)) {
+            // use AND operator for advanced searches
+            $where = implode(' AND ', $where);
+
+            $this->set_search_set($where);
+
+            if ($select) {
+                $this->list_records(null, 0, $nocount);
+            }
+            else {
+                $this->result = $this->count();
+            }
+        }
+
+        return $this->result;
+    }
+
+    /**
+     * Count number of available contacts in database
+     *
+     * @return int Contacts count
+     */
+    protected function _count()
+    {
+        // count contacts for this user
+        $sql_result = $this->db->query(
+            "SELECT COUNT(`address_id`) AS cnt"
+            . " FROM " . $this->db->table_name($this->db_name, true)
+            . " WHERE `user_id` = ? AND `type` = ?"
+            . ($this->filter ? " AND (" . $this->filter . ")" : ""),
+            $this->user_id,
+            $this->type
+        );
+
+        $sql_arr = $this->db->fetch_assoc($sql_result);
+
+        $this->cache['count'] = (int) $sql_arr['cnt'];
+
+        return $this->cache['count'];
+    }
+
+    /**
+     * Get a specific contact record
+     *
+     * @param mixed $id    Record identifier(s)
+     * @param bool  $assoc Enables returning associative array
+     *
+     * @return rcube_result_set|array Result object with all record fields
+     */
+    function get_record($id, $assoc = false)
+    {
+        // return cached result
+        if ($this->result && ($first = $this->result->first()) && $first[$this->primary_key] == $id) {
+            return $assoc ? $first : $this->result;
+        }
+
+        $this->db->query(
+            "SELECT * FROM " . $this->db->table_name($this->db_name, true)
+            . " WHERE `address_id` = ? AND `user_id` = ?",
+            $id,
+            $this->user_id
+        );
+
+        $this->result = null;
+
+        if ($record = $this->db->fetch_assoc()) {
+            $record['ID'] = $record['address_id'];
+            $this->result = new rcube_result_set(1);
+            $this->result->add($record);
+        }
+
+        return $assoc && !empty($record) ? $record : $this->result;
+    }
+
+    /**
+     * Check the given data before saving.
+     * If input not valid, the message to display can be fetched using get_error()
+     *
+     * @param array   &$save_data Associative array with data to save
+     * @param boolean $autofix    Try to fix/complete record automatically
+     *
+     * @return boolean True if input is valid, False if not.
+     */
+    public function validate(&$save_data, $autofix = false)
+    {
+        $email = array_filter($this->get_col_values('email', $save_data, true));
+
+        // require email
+        if (empty($email) || count($email) > 1) {
+            $this->set_error(self::ERROR_VALIDATE, 'noemailwarning');
+            return false;
+        }
+
+        $email = $email[0];
+
+        // check validity of the email address
+        if (!rcube_utils::check_email(rcube_utils::idn_to_ascii($email))) {
+            $error = $rcube->gettext(array('name' => 'emailformaterror', 'vars' => array('email' => $email)));
+            $this->set_error(self::ERROR_VALIDATE, $error);
+            return false;
+        }
+
+        return true;
+    }
+
+    /**
+     * Create a new contact record
+     *
+     * @param array $save_data Associative array with save data
+     * @param bool  $check     Enables validity checks
+     *
+     * @return integer|bool The created record ID on success, False on error
+     */
+    function insert($save_data, $check = false)
+    {
+        if (!is_array($save_data)) {
+            return false;
+        }
+
+        if ($check && ($existing = $this->search('email', $save_data['email'], false, false))) {
+            if ($existing->count) {
+                return false;
+            }
+        }
+
+        $this->cache = null;
+
+        $this->db->query(
+            "INSERT INTO " . $this->db->table_name($this->db_name, true)
+            . " (`user_id`, `changed`, `type`, `name`, `email`)"
+            . " VALUES (?, " . $this->db->now() . ", ?, ?, ?)",
+            $this->user_id,
+            $this->type,
+            $save_data['name'],
+            $save_data['email']
+        );
+
+        return $this->db->insert_id($this->db_name);
+    }
+
+    /**
+     * Update a specific contact record
+     *
+     * @param mixed $id        Record identifier
+     * @param array $save_cols Associative array with save data
+     *
+     * @return boolean True on success, False on error
+     */
+    function update($id, $save_cols)
+    {
+        return false;
+    }
+
+    /**
+     * Delete one or more contact records
+     *
+     * @param array   $ids   Record identifiers
+     * @param boolean $force Remove record(s) irreversible (unsupported)
+     *
+     * @return int Number of removed records
+     */
+    function delete($ids, $force = true)
+    {
+        if (!is_array($ids)) {
+            $ids = explode(self::SEPARATOR, $ids);
+        }
+
+        $ids = $this->db->array2list($ids, 'integer');
+
+        // flag record as deleted (always)
+        $this->db->query(
+            "DELETE FROM " . $this->db->table_name($this->db_name, true)
+            . " WHERE `user_id` = ? AND `type` = ? AND `address_id` IN ($ids)",
+            $this->user_id, $this->type
+        );
+
+        $this->cache = null;
+
+        return $this->db->affected_rows();
+    }
+
+    /**
+     * Remove all records from the database
+     *
+     * @param bool $with_groups Remove also groups
+     *
+     * @return int Number of removed records
+     */
+    function delete_all($with_groups = false)
+    {
+        $this->db->query("DELETE FROM " . $this->db->table_name($this->db_name, true)
+            . " WHERE `user_id` = ? AND `type` = ?",
+            $this->user_id, $this->type
+        );
+
+        $this->cache = null;
+
+        return $this->db->affected_rows();
+    }
+}
diff --git a/program/lib/Roundcube/rcube_config.php b/program/lib/Roundcube/rcube_config.php
index 2d164a308..4319d92fc 100644
--- a/program/lib/Roundcube/rcube_config.php
+++ b/program/lib/Roundcube/rcube_config.php
@@ -413,6 +413,18 @@ class rcube_config
                 $result = $this->prop['supported_layouts'][0];
             }
         }
+        else if ($name == 'collected_senders') {
+            if (is_bool($result)) {
+                $result = $result ? rcube_addressbook::TYPE_TRUSTED_SENDER : '';
+            }
+            $result = (string) $result;
+        }
+        else if ($name == 'collected_recipients') {
+            if (is_bool($result)) {
+                $result = $result ? rcube_addressbook::TYPE_RECIPIENT : '';
+            }
+            $result = (string) $result;
+        }
 
         $plugin = $rcube->plugins->exec_hook('config_get', array(
             'name' => $name, 'default' => $def, 'result' => $result));
diff --git a/program/lib/Roundcube/rcube_contacts.php b/program/lib/Roundcube/rcube_contacts.php
index bfc077084..8aed25503 100644
--- a/program/lib/Roundcube/rcube_contacts.php
+++ b/program/lib/Roundcube/rcube_contacts.php
@@ -36,13 +36,13 @@ class rcube_contacts extends rcube_addressbook
      *
      * @var rcube_db
      */
-    private $db      = null;
-    private $user_id = 0;
-    private $filter  = null;
-    private $result  = null;
-    private $cache;
-    private $table_cols    = array('name', 'email', 'firstname', 'surname');
-    private $fulltext_cols = array('name', 'firstname', 'surname', 'middlename', 'nickname',
+    protected $db      = null;
+    protected $user_id = 0;
+    protected $filter  = null;
+    protected $result  = null;
+    protected $cache;
+    protected $table_cols    = array('name', 'email', 'firstname', 'surname');
+    protected $fulltext_cols = array('name', 'firstname', 'surname', 'middlename', 'nickname',
         'jobtitle', 'organization', 'department', 'maidenname', 'email', 'phone',
         'address', 'street', 'locality', 'zipcode', 'region', 'country', 'website', 'im', 'notes');
 
@@ -448,11 +448,10 @@ class rcube_contacts extends rcube_addressbook
     /**
      * Helper method to compose SQL where statements for fulltext searching
      */
-    private function fulltext_sql_where($value, $mode, $col = 'words', $bool = 'AND')
+    protected function fulltext_sql_where($value, $mode, $col = 'words', $bool = 'AND')
     {
-        $WS = ' ';
-        $AS = $col == 'words' ? $WS : self::SEPARATOR;
-        $words = $col == 'words' ? rcube_utils::normalize_string($value, true) : array($value);
+        $AS    = $col == 'words' ? ' ' : self::SEPARATOR;
+        $words = $col == 'words' ? rcube_utils::normalize_string($value, true, 1) : array($value);
 
         $where = array();
         foreach ($words as $word) {
@@ -491,7 +490,7 @@ class rcube_contacts extends rcube_addressbook
      *
      * @return int Contacts count
      */
-    private function _count()
+    protected function _count()
     {
         $join = null;
 
@@ -794,6 +793,8 @@ class rcube_contacts extends rcube_addressbook
      *
      * @param array   $ids   Record identifiers
      * @param boolean $force Remove record(s) irreversible (unsupported)
+     *
+     * @return int Number of removed records
      */
     function delete($ids, $force = true)
     {
@@ -821,6 +822,8 @@ class rcube_contacts extends rcube_addressbook
      * Undelete one or more contact records
      *
      * @param array $ids Record identifiers
+     *
+     * @return int Number of undeleted contact records
      */
     function undelete($ids)
     {
diff --git a/program/localization/en_US/labels.inc b/program/localization/en_US/labels.inc
index 87a6272b8..9b7f4b148 100644
--- a/program/localization/en_US/labels.inc
+++ b/program/localization/en_US/labels.inc
@@ -599,6 +599,11 @@ $labels['replysamefolder'] = 'Place replies in the folder of the message being r
 $labels['defaultabook'] = 'Default address book';
 $labels['autocompletesingle'] = 'Skip alternative email addresses in autocompletion';
 $labels['listnamedisplay'] = 'List contacts as';
+$labels['collectedaddresses'] = 'Collected addresses';
+$labels['collectedrecipients'] = 'Collected recipients';
+$labels['collectedrecipientsopt'] = 'Store outgoing email recipients in';
+$labels['collectedsendersopt'] = 'Store trusted senders in';
+$labels['trustedsenders'] = 'Trusted senders';
 $labels['spellcheckbeforesend'] = 'Check spelling before sending a message';
 $labels['spellcheckoptions'] = 'Spellcheck Options';
 $labels['spellcheckignoresyms'] = 'Ignore words with symbols';
diff --git a/program/steps/addressbook/delete.inc b/program/steps/addressbook/delete.inc
index 32e8ce8be..1c3abf401 100644
--- a/program/steps/addressbook/delete.inc
+++ b/program/steps/addressbook/delete.inc
@@ -32,7 +32,7 @@ $RCMAIL->session->remove('contact_undo');
 foreach ($cids as $source => $cid) {
     $CONTACTS = rcmail_contact_source($source);
 
-    if ($CONTACTS->readonly) {
+    if ($CONTACTS->readonly && empty($CONTACTS->deletable)) {
         // more sources? do nothing, probably we have search results from
         // more than one source, some of these sources can be readonly
         if (count($cids) == 1) {
diff --git a/program/steps/addressbook/edit.inc b/program/steps/addressbook/edit.inc
index 78d3c2ad1..562538668 100644
--- a/program/steps/addressbook/edit.inc
+++ b/program/steps/addressbook/edit.inc
@@ -46,7 +46,7 @@ else {
     }
 
     if (!$CONTACTS || $CONTACTS->readonly) {
-        $CONTACTS = $RCMAIL->get_address_book(-1, true);
+        $CONTACTS = $RCMAIL->get_address_book(rcube_addressbook::TYPE_DEFAULT, true);
         $source   = $RCMAIL->get_address_book_id($CONTACTS);
     }
 
@@ -215,13 +215,16 @@ function get_form_tags($attrib)
     if (empty($EDIT_FORM)) {
         $hiddenfields = new html_hiddenfield();
 
-        if ($RCMAIL->action == 'edit')
+        if ($RCMAIL->action == 'edit') {
             $hiddenfields->add(array('name' => '_source', 'value' => $SOURCE_ID));
+        }
+
         $hiddenfields->add(array('name' => '_gid', 'value' => $CONTACTS->group_id));
         $hiddenfields->add(array('name' => '_search', 'value' => rcube_utils::get_input_value('_search', rcube_utils::INPUT_GPC)));
 
-        if (($result = $CONTACTS->get_result()) && ($record = $result->first()))
+        if (($result = $CONTACTS->get_result()) && ($record = $result->first())) {
             $hiddenfields->add(array('name' => '_cid', 'value' => $record['ID']));
+        }
 
         $form_start = $RCMAIL->output->request_form(array(
             'name' => "form", 'method' => "post",
@@ -255,8 +258,9 @@ function rcmail_source_selector($attrib)
 
     $select = new html_select($attrib);
 
-    foreach ($sources_list as $source)
+    foreach ($sources_list as $source) {
         $select->add($source['name'], $source['id']);
+    }
 
     return $select->show($SOURCE_ID);
 }
diff --git a/program/steps/addressbook/func.inc b/program/steps/addressbook/func.inc
index 70c2192d1..b35ac0bda 100644
--- a/program/steps/addressbook/func.inc
+++ b/program/steps/addressbook/func.inc
@@ -212,10 +212,11 @@ function rcmail_directory_list($attrib)
 {
     global $RCMAIL, $OUTPUT;
 
-    if (!$attrib['id'])
+    if (!$attrib['id']) {
         $attrib['id'] = 'rcmdirectorylist';
+    }
 
-    $out = '';
+    $out    = '';
     $jsdata = array();
 
     $line_templ = html::tag('li', array(
diff --git a/program/steps/addressbook/move.inc b/program/steps/addressbook/move.inc
index 0de7d31d0..db54d142f 100644
--- a/program/steps/addressbook/move.inc
+++ b/program/steps/addressbook/move.inc
@@ -53,7 +53,7 @@ foreach ($cids as $source => $source_cids) {
         break;
     }
 
-    if (!$CONTACTS || !$CONTACTS->ready || $CONTACTS->readonly) {
+    if (!$CONTACTS || !$CONTACTS->ready || ($CONTACTS->readonly && empty($CONTACTS->deletable))) {
         continue;
     }
 
diff --git a/program/steps/addressbook/search.inc b/program/steps/addressbook/search.inc
index 1564a3eeb..aa881dbca 100644
--- a/program/steps/addressbook/search.inc
+++ b/program/steps/addressbook/search.inc
@@ -144,7 +144,7 @@ function rcmail_contact_search()
     $search_set = array();
     $records    = array();
     $sort_col   = $RCMAIL->config->get('addressbook_sort_col', 'name');
-    $afields = $RCMAIL->config->get('contactlist_fields');
+    $afields    = $RCMAIL->config->get('contactlist_fields');
 
     foreach ($sources as $s) {
         $source = $RCMAIL->get_address_book($s['id']);
diff --git a/program/steps/mail/addcontact.inc b/program/steps/mail/addcontact.inc
index 3193b4177..03947b423 100644
--- a/program/steps/mail/addcontact.inc
+++ b/program/steps/mail/addcontact.inc
@@ -22,74 +22,60 @@ if (!$OUTPUT->ajax_call) {
     return;
 }
 
-// Get default addressbook
-$CONTACTS = $RCMAIL->get_address_book(-1, true);
+// Get the default addressbook
+$CONTACTS = $RCMAIL->get_address_book(rcube_addressbook::TYPE_DEFAULT, true);
+$SENDERS  = null;
+$type     = rcube_addressbook::TYPE_DEFAULT;
 
-if (!empty($_POST['_address']) && is_object($CONTACTS)) {
-    $address = rcube_utils::get_input_value('_address', rcube_utils::INPUT_POST, true);
-    $contact_arr = rcube_mime::decode_address_list($address, 1, false);
+// Get the trusted senders addressbook
+if (!empty($_POST['_reload'])) {
+    $collected_senders = $rcmail->config->get('collected_senders');
 
-    if (!empty($contact_arr[1]['mailto'])) {
-        $contact = array(
-            'email' => $contact_arr[1]['mailto'],
-            'name'  => $contact_arr[1]['name'],
-        );
-
-        // Validity checks
-        if (empty($contact['email'])) {
-            $OUTPUT->show_message('errorsavingcontact', 'error');
-            $OUTPUT->send();
-        }
-
-        $email = rcube_utils::idn_to_ascii($contact['email']);
-        if (!rcube_utils::check_email($email, false)) {
-            $OUTPUT->show_message('emailformaterror', 'error', array('email' => $contact['email']));
-            $OUTPUT->send();
-        }
-
-        $contact['email'] = rcube_utils::idn_to_utf8($contact['email']);
-
-        $contact = $RCMAIL->plugins->exec_hook('contact_displayname', $contact);
-
-        if (empty($contact['firstname']) || empty($contact['surname'])) {
-            $contact['name'] = rcube_addressbook::compose_display_name($contact);
-        }
-
-        // validate contact record
-        if (!$CONTACTS->validate($contact, true)) {
-            $error = $CONTACTS->get_error();
-            // TODO: show dialog to complete record
-            // if ($error['type'] == rcube_addressbook::ERROR_VALIDATE) { }
-
-            $OUTPUT->show_message($error['message'] ?: 'errorsavingcontact', 'error');
-            $OUTPUT->send();
-        }
-
-        // check for existing contacts
-        $existing = $CONTACTS->search('email', $contact['email'], 1, false);
-
-        if ($done = $existing->count) {
-            $OUTPUT->show_message('contactexists', 'warning');
-        }
-        else {
-            $plugin = $RCMAIL->plugins->exec_hook('contact_create', array('record' => $contact, 'source' => null));
-            $contact = $plugin['record'];
-
-            $done = !$plugin['abort'] ? $CONTACTS->insert($contact) : $plugin['result'];
-
-            if ($done) {
-                $OUTPUT->show_message('addedsuccessfully', 'confirmation');
-
-                if (!empty($_POST['_reload'])) {
-                    $OUTPUT->command('command', 'load-remote');
-                }
-            }
+    if (strlen($collected_senders)) {
+        $type |= rcube_addressbook::TYPE_TRUSTED_SENDER;
+        $SENDERS = $RCMAIL->get_address_book($collected_senders);
+        if ($CONTACTS == $SENDERS) {
+            $SENDERS = null;
         }
     }
 }
 
-if (!$done) {
-    $OUTPUT->show_message($plugin['message'] ?: 'errorsavingcontact', 'error');
+$address = rcube_utils::get_input_value('_address', rcube_utils::INPUT_POST, true);
+$contact = rcube_mime::decode_address_list($address, 1, false);
+
+if (empty($contact[1]['mailto'])) {
+    $OUTPUT->show_message('errorsavingcontact', 'error');
+    $OUTPUT->send();
+}
+
+$contact = array(
+    'email' => $contact[1]['mailto'],
+    'name'  => $contact[1]['name'],
+);
+
+$email = rcube_utils::idn_to_ascii($contact['email']);
+
+if (!rcube_utils::check_email($email, false)) {
+    $OUTPUT->show_message('emailformaterror', 'error', array('email' => $contact['email']));
+    $OUTPUT->send();
+}
+
+if ($RCMAIL->contact_exists($contact['email'], $type)) {
+    $OUTPUT->show_message('contactexists', 'warning');
+    $OUTPUT->send();
+}
+
+$done = $RCMAIL->contact_create($contact, $SENDERS ?: $CONTACTS, $error);
+
+if ($done) {
+    $OUTPUT->show_message('addedsuccessfully', 'confirmation');
+
+    if (!empty($_POST['_reload'])) {
+        $OUTPUT->command('command', 'load-remote');
+    }
+}
+else {
+    $OUTPUT->show_message($error ?: 'errorsavingcontact', 'error');
 }
 
 $OUTPUT->send();
diff --git a/program/steps/mail/autocomplete.inc b/program/steps/mail/autocomplete.inc
index 0a0b47cc3..e7c1d95bc 100644
--- a/program/steps/mail/autocomplete.inc
+++ b/program/steps/mail/autocomplete.inc
@@ -12,8 +12,8 @@
  | See the README file for a full license statement.                     |
  |                                                                       |
  | PURPOSE:                                                              |
- |   Perform a search on configured address books for the address        |
- |   autocompletion of the message compose screen                        |
+ |   Perform a search on configured address books for the email          |
+ |   address autocompletion                                              |
  +-----------------------------------------------------------------------+
  | Author: Thomas Bruederli <roundcube@gmail.com>                        |
  +-----------------------------------------------------------------------+
@@ -41,23 +41,15 @@ if ($RCMAIL->action == 'group-expand') {
     $OUTPUT->send();
 }
 
-
 $MAXNUM = (int) $RCMAIL->config->get('autocomplete_max', 15);
 $mode   = (int) $RCMAIL->config->get('addressbook_search_mode');
 $single = (bool) $RCMAIL->config->get('autocomplete_single');
 $search = rcube_utils::get_input_value('_search', rcube_utils::INPUT_GPC, true);
-$source = rcube_utils::get_input_value('_source', rcube_utils::INPUT_GPC);
 $reqid  = rcube_utils::get_input_value('_reqid', rcube_utils::INPUT_GPC);
 
-if (strlen($source)) {
-    $book_types = array($source);
-}
-else {
-    $book_types = (array) $RCMAIL->config->get('autocomplete_addressbooks', 'sql');
-}
-
 $contacts = array();
-if (!empty($book_types) && strlen($search)) {
+
+if (strlen($search) && ($book_types = rcmail_autocomplete_addressbooks())) {
     $sort_keys = array();
     $books_num = count($book_types);
     $search_lc = mb_strtolower($search);
@@ -148,7 +140,7 @@ if (!empty($book_types) && strlen($search)) {
                             );
 
                             if (count($contacts) >= $MAXNUM) {
-                                break 2;
+                                break 3;
                             }
                         }
                     }
@@ -165,7 +157,7 @@ if (!empty($book_types) && strlen($search)) {
                         );
 
                         if (count($contacts) >= $MAXNUM) {
-                            break;
+                            break 2;
                         }
                     }
                 }
@@ -186,12 +178,43 @@ if (!empty($book_types) && strlen($search)) {
 
 
 // Allow autocomplete result optimization via plugin
-$pluginResult = $RCMAIL->plugins->exec_hook('contacts_autocomplete_after', array(
+$plugin = $RCMAIL->plugins->exec_hook('contacts_autocomplete_after', array(
     'search'   => $search,
     'contacts' => $contacts, // Provide already-found contacts to plugin if they are required
 ));
-$contacts = $pluginResult['contacts'];
 
+$contacts = $plugin['contacts'];
 
 $OUTPUT->command('ksearch_query_results', $contacts, $search, $reqid);
 $OUTPUT->send();
+
+
+/**
+ * Collect addressbook sources used for autocompletion
+ */
+function rcmail_autocomplete_addressbooks()
+{
+    global $RCMAIL;
+
+    $source = rcube_utils::get_input_value('_source', rcube_utils::INPUT_GPC);
+
+    if (strlen($source)) {
+        $book_types = array($source);
+    }
+    else {
+        $book_types = (array) $RCMAIL->config->get('autocomplete_addressbooks', 'sql');
+    }
+
+    $collected_recipients = $RCMAIL->config->get('collected_recipients');
+    $collected_senders    = $RCMAIL->config->get('collected_senders');
+
+    if (strlen($collected_recipients) && !in_array($collected_recipients, $book_types)) {
+        $book_types[] = $collected_recipients;
+    }
+
+    if (strlen($collected_senders) && !in_array($collected_senders, $book_types)) {
+        $book_types[] = $collected_senders;
+    }
+
+    return !empty($book_types) ? $book_types : null;
+}
diff --git a/program/steps/mail/func.inc b/program/steps/mail/func.inc
index 1fa1c7e3b..bd6b0210f 100644
--- a/program/steps/mail/func.inc
+++ b/program/steps/mail/func.inc
@@ -798,12 +798,9 @@ function rcmail_check_safe($message)
     ) {
         switch ($show_images) {
         case 1: // known senders only
-            // get default addressbook, like in addcontact.inc
-            $CONTACTS = $RCMAIL->get_address_book(-1, true);
-
-            if ($CONTACTS && $message->sender['mailto']) {
-                $result = $CONTACTS->search('email', $message->sender['mailto'], 1, false);
-                if ($result->count) {
+            if (!empty($message->sender['mailto'])) {
+                $type = rcube_addressbook::TYPE_DEFAULT | rcube_addressbook::TYPE_TRUSTED_SENDER;
+                if ($RCMAIL->contact_exists($message->sender['mailto'], $type)) {
                     $message->set_safe(true);
                 }
             }
diff --git a/program/steps/mail/show.inc b/program/steps/mail/show.inc
index 292ba9475..3012a5d2d 100644
--- a/program/steps/mail/show.inc
+++ b/program/steps/mail/show.inc
@@ -116,7 +116,9 @@ if ($uid) {
     ) {
         $mdn_cfg = intval($RCMAIL->config->get('mdn_requests'));
 
-        if ($mdn_cfg == 1 || (($mdn_cfg == 3 || $mdn_cfg ==  4) && rcmail_contact_exists($MESSAGE->sender['mailto']))) {
+        if ($mdn_cfg == 1 || (($mdn_cfg == 3 || $mdn_cfg ==  4)
+            && $RCMAIL->contact_exists($MESSAGE->sender['mailto'], rcube_addressbook::TYPE_DEFAULT))
+        ) {
             // Send MDN
             if (rcmail_send_mdn($MESSAGE, $smtp_error)) {
                 $OUTPUT->show_message('receiptsent', 'confirmation');
@@ -332,25 +334,6 @@ function rcmail_message_objects($attrib)
     return html::div($attrib, $content);
 }
 
-function rcmail_contact_exists($email)
-{
-    global $RCMAIL;
-
-    if ($email) {
-        // @TODO: search in all address books?
-        $CONTACTS = $RCMAIL->get_address_book(-1, true);
-
-        if (is_object($CONTACTS)) {
-            $existing = $CONTACTS->search('email', $email, 1, false);
-            if ($existing->count) {
-                return true;
-            }
-        }
-    }
-
-    return false;
-}
-
 function rcmail_message_contactphoto($attrib)
 {
     global $RCMAIL, $MESSAGE;
diff --git a/program/steps/settings/func.inc b/program/steps/settings/func.inc
index 05312ada1..8eb97f153 100644
--- a/program/steps/settings/func.inc
+++ b/program/steps/settings/func.inc
@@ -977,8 +977,9 @@ function rcmail_user_prefs($current = null)
         // Addressbook config
         case 'addressbook':
             $blocks = array(
-                'main'     => array('name' => rcube::Q($RCMAIL->gettext('mainoptions'))),
-                'advanced' => array('name' => rcube::Q($RCMAIL->gettext('advancedoptions'))),
+                'main'      => array('name' => rcube::Q($RCMAIL->gettext('mainoptions'))),
+                'collected' => array('name' => rcube::Q($RCMAIL->gettext('collectedaddresses'))),
+                'advanced'  => array('name' => rcube::Q($RCMAIL->gettext('advancedoptions'))),
             );
 
             if (!isset($no_override['default_addressbook'])
@@ -1069,6 +1070,66 @@ function rcmail_user_prefs($current = null)
                     'content' => $checkbox->show($config['autocomplete_single']?1:0),
                 );
             }
+
+            if (!isset($no_override['collected_recipients'])) {
+                if (!$current) {
+                    continue 2;
+                }
+
+                if (!isset($books)) {
+                    $books = $RCMAIL->get_address_sources(true, true);
+                }
+
+                $field_id = 'rcmfd_collected_recipients';
+                $select   = new html_select(array('name' => '_collected_recipients', 'id' => $field_id, 'class' => 'custom-select'));
+
+                $select->add('---', '');
+                $select->add($RCMAIL->gettext('collectedrecipients'), (string) rcube_addressbook::TYPE_RECIPIENT);
+
+                foreach ($books as $book) {
+                    $select->add(html_entity_decode($book['name'], ENT_COMPAT, 'UTF-8'), $book['id']);
+                }
+
+                $selected = $config['collected_recipients'];
+                if (is_bool($selected)) {
+                    $selected = $selected ? rcube_addressbook::TYPE_RECIPIENT : '';
+                }
+
+                $blocks['collected']['options']['collected_recipients'] = array(
+                    'title'   => html::label($field_id, rcube::Q($RCMAIL->gettext('collectedrecipientsopt'))),
+                    'content' => $select->show((string) $selected),
+                );
+            }
+
+            if (!isset($no_override['collected_senders'])) {
+                if (!$current) {
+                    continue 2;
+                }
+
+                if (!isset($books)) {
+                    $books = $RCMAIL->get_address_sources(true, true);
+                }
+
+                $field_id = 'rcmfd_collected_senders';
+                $select   = new html_select(array('name' => '_collected_senders', 'id' => $field_id, 'class' => 'custom-select'));
+
+                $select->add($RCMAIL->gettext('trustedsenders'), (string) rcube_addressbook::TYPE_TRUSTED_SENDER);
+
+                foreach ($books as $book) {
+                    $select->add(html_entity_decode($book['name'], ENT_COMPAT, 'UTF-8'), $book['id']);
+                }
+
+                $selected = $config['collected_senders'];
+                if (is_bool($selected)) {
+                    $selected = $selected ? rcube_addressbook::TYPE_TRUSTED_SENDER : '';
+                }
+
+                $blocks['collected']['options']['collected_senders'] = array(
+                    'title'   => html::label($field_id, rcube::Q($RCMAIL->gettext('collectedsendersopt'))),
+                    'content' => $select->show((string) $elected),
+                );
+            }
+
         break;
 
         // Special IMAP folders
diff --git a/program/steps/settings/save_prefs.inc b/program/steps/settings/save_prefs.inc
index fdbb5eed0..dbf22c2d5 100644
--- a/program/steps/settings/save_prefs.inc
+++ b/program/steps/settings/save_prefs.inc
@@ -100,6 +100,8 @@ case 'compose':
 case 'addressbook':
     $a_user_prefs = array(
         'default_addressbook'  => rcube_utils::get_input_value('_default_addressbook', rcube_utils::INPUT_POST, true),
+        'collected_recipients' => rcube_utils::get_input_value('_collected_recipients', rcube_utils::INPUT_POST, true),
+        'collected_senders'    => rcube_utils::get_input_value('_collected_senders', rcube_utils::INPUT_POST, true),
         'autocomplete_single'  => isset($_POST['_autocomplete_single']),
         'addressbook_sort_col' => rcmail_prefs_input('addressbook_sort_col', '/^[a-z_]+$/'),
         'addressbook_name_listing' => intval($_POST['_addressbook_name_listing']),
diff --git a/tests/Framework/Addresses.php b/tests/Framework/Addresses.php
new file mode 100644
index 000000000..f29b73cea
--- /dev/null
+++ b/tests/Framework/Addresses.php
@@ -0,0 +1,21 @@
+<?php
+
+/**
+ * Test class to test rcube_addresses class
+ *
+ * @package Tests
+ */
+class Framework_Addresses extends PHPUnit\Framework\TestCase
+{
+
+    /**
+     * Class constructor
+     */
+    function test_class()
+    {
+        $object = new rcube_addresses(1, null, 1);
+
+        $this->assertInstanceOf('rcube_addresses', $object, "Class constructor");
+        $this->assertInstanceOf('rcube_addressbook', $object, "Class constructor");
+    }
+}