diff --git a/lib/Compose/Attachment.php b/lib/Compose/Attachment.php
index dbd013285..25d8e8ca1 100644
--- a/lib/Compose/Attachment.php
+++ b/lib/Compose/Attachment.php
@@ -187,6 +187,11 @@ public function viewUrl()
     /**
      */
     public function serialize()
+    {
+        return array_shift($this->__serialize());
+    }
+
+    public function __serialize(): array
     {
         /* Don't store Mime_Part data. Can't use clone here ATM, since there
          * appears to be a PHP bug. Since this is an object specific to IMP
@@ -196,7 +201,9 @@ public function serialize()
         $this->_part->clearContents();
         $this->_isBuilt = false;
 
-        return $GLOBALS['injector']->getInstance('Horde_Pack')->pack(
+        return
+        [
+            $GLOBALS['injector']->getInstance('Horde_Pack')->pack(
             array(
                 $this->_composeCache,
                 $this->id,
@@ -207,13 +214,18 @@ public function serialize()
             ), array(
                 'compression' => false,
                 'phpob' => true
-            )
-        );
+            ))
+        ];
     }
 
     /**
      */
     public function unserialize($data)
+    {
+        $this->__unserialize([$data]);
+    }
+
+    public function __unserialize(array $data): void
     {
         list(
             $this->_composeCache,
@@ -222,7 +234,6 @@ public function unserialize($data)
             $this->_part,
             $this->related,
             $this->_uuid
-        ) = $GLOBALS['injector']->getInstance('Horde_Pack')->unpack($data);
+        ) = $GLOBALS['injector']->getInstance('Horde_Pack')->unpack(array_shift($data));
     }
-
 }
diff --git a/lib/Flag/Base.php b/lib/Flag/Base.php
index b49ed4c0d..c88494f3f 100644
--- a/lib/Flag/Base.php
+++ b/lib/Flag/Base.php
@@ -203,7 +203,12 @@ public function serialize()
     {
         return $this->_bgcolor;
     }
-
+    public function __serialize(): array
+    {
+        return [
+            $this->_bgcolor
+        ];
+    } 
     /**
      */
     public function unserialize($data)
@@ -211,4 +216,8 @@ public function unserialize($data)
         $this->_bgcolor = $data;
     }
 
+    public function __unserialize(array $data): void 
+    {
+        $this->_bgcolor = $data[0];
+    }
 }
diff --git a/lib/Flag/User.php b/lib/Flag/User.php
index b983430ec..0b61665a4 100644
--- a/lib/Flag/User.php
+++ b/lib/Flag/User.php
@@ -112,22 +112,33 @@ protected function _getLabel()
      */
     public function serialize()
     {
-        return json_encode(array(
-            parent::serialize(),
-            $this->_label,
-            $this->_imapflag
-        ));
+        return array_shift($this->__serialize());
+    }
+    public function __serialize(): array 
+    {
+        return
+        [
+            json_encode(array(
+                parent::serialize(),
+                $this->_label,
+                $this->_imapflag
+            ))
+        ];
     }
 
     /**
      */
     public function unserialize($data)
     {
-        $data = json_decode($data, true);
+        $this->__unserialize([$data]);
+    }
+    public function __unserialize(array $data): void 
+    {
+        $data = json_decode($data[0], true);
 
         parent::unserialize($data[0]);
         $this->_label = $data[1];
         $this->_imapflag = $data[2];
-    }
 
+    }
 }
diff --git a/lib/Ftree/Account.php b/lib/Ftree/Account.php
index f687c6cf7..399a29cc0 100644
--- a/lib/Ftree/Account.php
+++ b/lib/Ftree/Account.php
@@ -84,12 +84,21 @@ public function serialize()
     {
         return $this->_id;
     }
-
+    public function __serialize(): array
+    {
+        return
+        [
+            $this->_id
+        ];
+    }
     /**
      */
     public function unserialize($data)
     {
         $this->_id = $data;
     }
-
+    public function __unserialize(array $data): void 
+    {
+        $this->_id = $data[0];
+    }
 }
diff --git a/lib/Ftree/Eltdiff.php b/lib/Ftree/Eltdiff.php
index 66f26141b..9340e1a6f 100644
--- a/lib/Ftree/Eltdiff.php
+++ b/lib/Ftree/Eltdiff.php
@@ -193,26 +193,37 @@ public function clear()
      */
     public function serialize()
     {
-        return $GLOBALS['injector']->getInstance('Horde_Pack')->pack(
-            array(
-                $this->track,
-                $this->_changes
-            ),
-            array(
-                'compression' => false,
-                'phpob' => false
-            )
-        );
+        return array_shift($this->__serialize());
+    }
+    public function __serialize(): array
+    {
+        return
+        [
+            $GLOBALS['injector']->getInstance('Horde_Pack')->pack(
+                array(
+                    $this->track,
+                    $this->_changes
+                ),
+                array(
+                    'compression' => false,
+                    'phpob' => false
+                )
+            ) 
+        ];
     }
 
     /**
      */
     public function unserialize($data)
+    {
+        $this->__unserialize([$data]);
+    }
+    public function __unserialize(array $data): void 
     {
         list(
             $this->track,
             $this->_changes
-        ) = $GLOBALS['injector']->getInstance('Horde_Pack')->unpack($data);
+        ) = $GLOBALS['injector']->getInstance('Horde_Pack')->unpack(array_shift($data));
     }
 
 }
diff --git a/lib/Imap.php b/lib/Imap.php
index 5adca73c2..97594ceb6 100644
--- a/lib/Imap.php
+++ b/lib/Imap.php
@@ -943,28 +943,40 @@ public static function loadServerConfig($server = null)
      */
     public function serialize()
     {
-        return $GLOBALS['injector']->getInstance('Horde_Pack')->pack(
-            array(
-                $this->_ob,
-                $this->_id,
-                $this->_config
-            ),
-            array(
-                'compression' => false,
-                'phpob' => true
+        return array_shift($this->__serialize());
+    }
+    public function __serialize(): array
+    {
+        return
+        [
+            $GLOBALS['injector']->getInstance('Horde_Pack')->pack(
+                array(
+                    $this->_ob,
+                    $this->_id,
+                    $this->_config
+                ),
+                array(
+                    'compression' => false,
+                    'phpob' => true
+                )
             )
-        );
+        ];
     }
-
     /**
+     * @throws Horde_Pack_Exception
      */
     public function unserialize($data)
+    {
+        $this->__unserialize([$data]);
+    }
+
+    public function __unserialize(array $data): void
     {
         list(
             $this->_ob,
             $this->_id,
             $this->_config
-        ) = $GLOBALS['injector']->getInstance('Horde_Pack')->unpack($data);
+        ) = $GLOBALS['injector']->getInstance('Horde_Pack')->unpack(array_shift($data));
+        
     }
-
 }
diff --git a/lib/Imap/Cache/Wrapper.php b/lib/Imap/Cache/Wrapper.php
index ee00148c3..1879e024c 100644
--- a/lib/Imap/Cache/Wrapper.php
+++ b/lib/Imap/Cache/Wrapper.php
@@ -125,14 +125,24 @@ public function __call($name, $arguments)
      */
     public function serialize()
     {
-        return json_encode($this->_params);
+        return array_shift($this->__serialize());
+    }
+    public function __serialize(): array 
+    {
+        return
+        [
+            json_encode($this->_params)
+        ];
     }
 
     /**
      */
     public function unserialize($data)
     {
-        $this->_initOb(json_decode($data, true));
+        $this->__unserialize([$data]);
+    }
+    public function __unserialize(array $data): void 
+    {
+        $this->_initOb(json_decode($data[0], true));
     }
-
 }
diff --git a/lib/Imap/Config.php b/lib/Imap/Config.php
index 88e4938b4..151aa229e 100644
--- a/lib/Imap/Config.php
+++ b/lib/Imap/Config.php
@@ -297,7 +297,7 @@ public function __get($name)
 
         case 'maildomain':
             /* Sanity checking - this should be null, not empty string. */
-            if (!strlen($out)) {
+            if (!is_null($out) && !strlen($out)) {
                 $out = null;
             }
             break;
@@ -376,6 +376,10 @@ public function __unset($name)
     /**
      */
     public function serialize()
+    {
+        return array_shift($this->__serialize());
+    }
+    public function __serialize(): array 
     {
         global $injector, $session;
 
@@ -383,24 +387,31 @@ public function serialize()
             $session->set('imp', self::PASSWORDS_KEY, $this->_passwords, $session::ENCRYPT);
         }
 
-        return $injector->getInstance('Horde_Pack')->pack(
-            array_filter($this->_config),
-            array(
-                'compression' => false,
-                'phpob' => false
+        return
+        [
+            $injector->getInstance('Horde_Pack')->pack(
+                array_filter($this->_config),
+                array(
+                    'compression' => false,
+                    'phpob' => false
+                )
             )
-        );
-    }
+        ];
 
+    }
     /**
      */
     public function unserialize($data)
+    {
+        $this->__unserialize([$data]);
+    }
+    public function __unserialize(array $data): void 
     {
         global $injector, $session;
 
-        $this->_config = $injector->getInstance('Horde_Pack')->unpack($data);
+        $this->_config = $injector->getInstance('Horde_Pack')->unpack(array_shift($data));
 
         $this->_passwords = $session->get('imp', self::PASSWORDS_KEY, $session::TYPE_ARRAY);
-    }
 
+    }
 }
diff --git a/lib/Imap/Password.php b/lib/Imap/Password.php
index 5d64e9220..75cde4e34 100644
--- a/lib/Imap/Password.php
+++ b/lib/Imap/Password.php
@@ -64,6 +64,10 @@ public function getPassword()
     /**
      */
     public function serialize()
+    {
+        return array_shift($this->__serialize());
+    }
+    public function __serialize(): array 
     {
         global $session;
 
@@ -73,15 +77,21 @@ public function serialize()
 
         $session->set('imp', self::PASSWORD_KEY . '/' . $this->_id, $this->_password, $session::ENCRYPT);
 
-        return $this->_id;
+        return
+        [
+            $this->_id
+        ];        
     }
-
     /**
      * @throws RuntimeException
      */
     public function unserialize($data)
     {
-        $this->_id = $data;
+        $this->__unserialize([$data]);
+    }
+    public function __unserialize(array $data): void 
+    {
+        $this->_id = $data[0];
 
         $password = $GLOBALS['session']->get(
             'imp',
@@ -94,6 +104,6 @@ public function unserialize($data)
             );
         }
         $this->_password = $password;
-    }
 
+    }
 }
diff --git a/lib/LoginTasks/SystemTask/Upgrade.php b/lib/LoginTasks/SystemTask/Upgrade.php
index 31112f9e3..4eb91a0c9 100644
--- a/lib/LoginTasks/SystemTask/Upgrade.php
+++ b/lib/LoginTasks/SystemTask/Upgrade.php
@@ -687,12 +687,23 @@ class IMP_Search_Element_Date implements Serializable
 
     public function serialize()
     {
-        return '';
+        return array_shift($this->__serialize());
+    }
+    public function __serialize(): array 
+    {
+        return
+        [
+            ''
+        ];
     }
 
     public function unserialize($data)
     {
-        $this->data = json_decode($data);
+        $this->__unserialize([$data]);
+    }
+    public function __unserialize(array $data): void 
+    {
+        $this->data = json_decode($data[0]);
     }
 
 }
diff --git a/lib/Mailbox/SessionCache.php b/lib/Mailbox/SessionCache.php
index b38010e61..2045aaa69 100644
--- a/lib/Mailbox/SessionCache.php
+++ b/lib/Mailbox/SessionCache.php
@@ -397,20 +397,30 @@ public function expire($entries, $mbox = null)
      */
     public function serialize()
     {
-        return $GLOBALS['injector']->getInstance('Horde_Pack')->pack(
-            $this->_cache,
-            array(
-                'compression' => false,
-                'phpob' => false
+        return array_shift($this->__serialize());
+    }
+    public function __serialize(): array 
+    {
+        return
+        [
+            $GLOBALS['injector']->getInstance('Horde_Pack')->pack(
+                $this->_cache,
+                array(
+                    'compression' => false,
+                    'phpob' => false
+                )
             )
-        );
+        ];
     }
 
     /**
      */
     public function unserialize($data)
     {
-        $this->_cache = $GLOBALS['injector']->getInstance('Horde_Pack')->unpack($data);
+        $this->__unserialize([$data]);
+    }
+    public function __unserialize(array $data): void 
+    {
+        $this->_cache = $GLOBALS['injector']->getInstance('Horde_Pack')->unpack(array_shift($data));
     }
-
 }
diff --git a/lib/Message/Date.php b/lib/Message/Date.php
index 3ac095557..b9a1f58c1 100644
--- a/lib/Message/Date.php
+++ b/lib/Message/Date.php
@@ -105,7 +105,7 @@ public function format($format = 0)
             }
 
             $this->_buildCache();
-            $tz = strftime('%Z');
+            $tz = strftime('%Z'); // TODO replace strftime
 
             if (($udate < self::$_cache['today_start']) ||
                 ($udate > self::$_cache['today_end'])) {
@@ -141,7 +141,7 @@ public function format($format = 0)
 
         if ($format === self::DATE_FORCE) {
             return $this->_format('date_format', $udate) . ' [' .
-                $this->_format('time_format', $udate) . ' ' . strftime('%Z') .
+                $this->_format('time_format', $udate) . ' ' . strftime('%Z') . // TODO replace strftime
                 ']';
         }
 
diff --git a/lib/Remote/Account.php b/lib/Remote/Account.php
index 45e38d966..6fc5451ca 100644
--- a/lib/Remote/Account.php
+++ b/lib/Remote/Account.php
@@ -232,14 +232,24 @@ public function mailbox($id)
      */
     public function serialize()
     {
-        return json_encode($this->_config);
+        return array_shift($this->__serialize());
+    }
+    public function __serialize(): array 
+    {
+        return
+        [
+            json_encode($this->_config)
+        ];
     }
 
     /**
      */
     public function unserialize($data)
     {
-        $this->_config = json_decode($data, true);
+        $this->__unserialize([$data]);
+    }
+    public function __unserialize(array $data): void 
+    {
+        $this->_config = json_decode($data[0], true);
     }
-
 }
diff --git a/lib/Search/Element.php b/lib/Search/Element.php
index 73619f579..baa8b339f 100644
--- a/lib/Search/Element.php
+++ b/lib/Search/Element.php
@@ -77,10 +77,17 @@ public function getCriteria()
      */
     public function serialize()
     {
-        return json_encode(array(
-            self::VERSION,
-            $this->_data
-        ));
+        return array_shift($this->__serialize()); 
+    }
+    public function __serialize(): array 
+    {
+        return
+        [
+            json_encode(array(
+                self::VERSION,
+                $this->_data
+            ))
+        ];
     }
 
     /**
@@ -92,7 +99,11 @@ public function serialize()
      */
     public function unserialize($data)
     {
-        $data = json_decode($data);
+        $this->__unserialize([$data]);
+    }
+    public function __unserialize(array $data): void 
+    {
+        $data = json_decode($data[0]);
         if (!is_array($data) ||
             !isset($data[0]) ||
             ($data[0] != self::VERSION)) {
@@ -101,5 +112,4 @@ public function unserialize($data)
 
         $this->_data = $data[1];
     }
-
 }
diff --git a/lib/Search/Filter/Builtin.php b/lib/Search/Filter/Builtin.php
index 98072780f..cb3b13172 100644
--- a/lib/Search/Filter/Builtin.php
+++ b/lib/Search/Filter/Builtin.php
@@ -54,4 +54,10 @@ public function unserialize($data)
         $this->_init();
     }
 
+    public function __unserialize(array $data): void 
+    {
+        parent::__unserialize($data);
+        $this->_init();
+    }
+
 }
diff --git a/lib/Search/Query.php b/lib/Search/Query.php
index c0fa62be6..cce9d492c 100644
--- a/lib/Search/Query.php
+++ b/lib/Search/Query.php
@@ -374,6 +374,23 @@ public function serialize()
 
         return serialize($data);
     }
+    public function __serialize(): array 
+    {
+        $data = array_filter(array(
+            'c' => $this->_criteria,
+            'e' => intval($this->enabled),
+            'i' => $this->_id,
+            'l' => $this->_label,
+            'm' => $this->_mboxes,
+            'v' => self::VERSION
+        ));
+
+        foreach ($this->_nosave as $val) {
+            unset($data[$val]);
+        }
+
+        return $data;
+    }
 
     /**
      * Unserialization.
@@ -405,5 +422,25 @@ public function unserialize($data)
             $this->_mboxes = $data['m'];
         }
     }
+    public function __unserialize(array $data): void 
+    {
+        if (!isset($data['v']) ||
+            ($data['v'] != self::VERSION)) {
+            throw new Exception('Cache version change');
+        }
 
+        if (isset($data['c'])) {
+            $this->_criteria = $data['c'];
+        }
+        $this->enabled = !empty($data['e']);
+        if (isset($data['i'])) {
+            $this->_id = $data['i'];
+        }
+        if (isset($data['l'])) {
+            $this->_label = $data['l'];
+        }
+        if (isset($data['m'])) {
+            $this->_mboxes = $data['m'];
+        }
+    }
 }
diff --git a/lib/Search/Vfolder/Builtin.php b/lib/Search/Vfolder/Builtin.php
index f1729d93b..739159497 100644
--- a/lib/Search/Vfolder/Builtin.php
+++ b/lib/Search/Vfolder/Builtin.php
@@ -67,5 +67,9 @@ public function unserialize($data)
         parent::unserialize($data);
         $this->_init();
     }
-
+    public function __unserialize(array $data): void 
+    {
+        parent::__unserialize($data);
+        $this->_init();
+    }
 }