diff --git a/.gitignore b/.gitignore
index b79a0b55d9..eadcdde6a3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,28 +1,4 @@
-# Ignore everything (useful to ignore the whole Contao installation)
-/*
-
-# Do not ignore ".gitignore"
-!.gitignore
-!.tx
-!composer.json
-!build.xml.dist
-!README.md
-
-# Isotope ignoring rules
-!isotope/
-isotope/*
-!isotope/.htaccess
-!isotope/index.html
-!system/
-system/*
-!system/modules
-system/modules/*
-!system/modules/isotope/*
-!system/modules/isotope_reports/*
-!system/modules/isotope_rules/*
-/system/modules/isotope/config/runonce.php
-
-# Gulp and node modules
-!gulpfile.js
-!package.json
-node_modules/
+/vendor/
+/node_modules/
+/composer.lock
+/.php_cs.cache
diff --git a/system/modules/isotope/docs/CHANGELOG-2.5.md b/system/modules/isotope/docs/CHANGELOG-2.5.md
index 4aac33b335..16b6f7719b 100644
--- a/system/modules/isotope/docs/CHANGELOG-2.5.md
+++ b/system/modules/isotope/docs/CHANGELOG-2.5.md
@@ -2,6 +2,12 @@ Isotope eCommerce Changelog
 ===========================
 
 
+Version 2.5.15-stable (2019-07-02)
+----------------------------------
+
+- Cumulative filter incorrectly handled checkbox fields (#1933)
+
+
 Version 2.5.14-stable (2019-06-11)
 ---------------------------------
 
diff --git a/system/modules/isotope/library/Isotope/Isotope.php b/system/modules/isotope/library/Isotope/Isotope.php
index 329114ad75..0ca5c45a87 100644
--- a/system/modules/isotope/library/Isotope/Isotope.php
+++ b/system/modules/isotope/library/Isotope/Isotope.php
@@ -44,7 +44,7 @@ class Isotope extends \Controller
     /**
      * Isotope version
      */
-    const VERSION = '2.5.14';
+    const VERSION = '2.5.15';
 
     /**
      * True if the system has been initialized
diff --git a/system/modules/isotope/library/Isotope/Model/Attribute/AbstractAttributeWithOptions.php b/system/modules/isotope/library/Isotope/Model/Attribute/AbstractAttributeWithOptions.php
index 75da493e8f..a3c8a858d0 100644
--- a/system/modules/isotope/library/Isotope/Model/Attribute/AbstractAttributeWithOptions.php
+++ b/system/modules/isotope/library/Isotope/Model/Attribute/AbstractAttributeWithOptions.php
@@ -287,8 +287,10 @@ public function getValue(IsotopeProduct $product)
         $value = parent::getValue($product);
 
         if ($this->multiple) {
-            if (IsotopeAttributeWithOptions::SOURCE_TABLE === $this->optionsSource
-                || IsotopeAttributeWithOptions::SOURCE_FOREIGNKEY === $this->optionsSource
+            if ((
+                IsotopeAttributeWithOptions::SOURCE_TABLE === $this->optionsSource
+                    || IsotopeAttributeWithOptions::SOURCE_FOREIGNKEY === $this->optionsSource
+                ) && $this->csv === ','
             ) {
                 $value = explode(',', $value);
             } else {
diff --git a/system/modules/isotope/library/Isotope/Model/Attribute/CheckboxMenu.php b/system/modules/isotope/library/Isotope/Model/Attribute/CheckboxMenu.php
index 4a814b8395..fe68280f21 100644
--- a/system/modules/isotope/library/Isotope/Model/Attribute/CheckboxMenu.php
+++ b/system/modules/isotope/library/Isotope/Model/Attribute/CheckboxMenu.php
@@ -36,14 +36,14 @@ public function prepareOptionsWizard($objWidget, $arrColumns)
      */
     public function saveToDCA(array &$arrData)
     {
-        parent::saveToDCA($arrData);
-
         $this->multiple = true;
 
+        parent::saveToDCA($arrData);
+
         if (!$this->variant_option && $this->optionsSource === IsotopeAttributeWithOptions::SOURCE_NAME) {
             $arrData['fields'][$this->field_name]['eval']['multiple'] = false;
             $arrData['fields'][$this->field_name]['sql'] = "char(1) NOT NULL default ''";
-            $arrData['fields'][$this->field_name]['options'];
+            unset($arrData['fields'][$this->field_name]['options']);
         } else {
             $arrData['fields'][$this->field_name]['eval']['multiple'] = true;
             $arrData['fields'][$this->field_name]['sql'] = 'blob NULL';
diff --git a/system/modules/isotope/library/Isotope/Upgrade/To0020050150.php b/system/modules/isotope/library/Isotope/Upgrade/To0020050150.php
new file mode 100644
index 0000000000..b0a1396924
--- /dev/null
+++ b/system/modules/isotope/library/Isotope/Upgrade/To0020050150.php
@@ -0,0 +1,66 @@
+<?php
+/**
+ * Isotope eCommerce for Contao Open Source CMS
+ *
+ * Copyright (C) 2009-2017 terminal42 gmbh & Isotope eCommerce Workgroup
+ *
+ * @link       https://isotopeecommerce.org
+ * @license    https://opensource.org/licenses/lgpl-3.0.html
+ */
+
+/**
+ * Isotope eCommerce for Contao Open Source CMS
+ *
+ * Copyright (C) 2009-2016 terminal42 gmbh & Isotope eCommerce Workgroup
+ *
+ * @link       https://isotopeecommerce.org
+ * @license    https://opensource.org/licenses/lgpl-3.0.html
+ */
+
+namespace Isotope\Upgrade;
+
+use Contao\Database;
+
+class To0020050150 extends Base
+{
+    public function run($blnInstalled)
+    {
+        if (!$blnInstalled) {
+            return;
+        }
+
+        $attributes = Database::getInstance()->execute(
+            "SELECT field_name FROM tl_iso_attribute WHERE type='checkbox' AND (optionsSource='table' OR optionsSource='foreignKey')"
+        )->fetchEach('field_name');
+
+        if (empty($attributes)) {
+            return;
+        }
+
+        $fields = implode(', ', $attributes);
+
+        $products = Database::getInstance()->execute("SELECT id, $fields FROM tl_iso_product")->fetchAllAssoc();
+
+        foreach ($products as $product) {
+            $update = [];
+
+            foreach ($attributes as $attribute) {
+                if (0 !== strpos($product[$attribute], 'a:')) {
+                    continue;
+                }
+
+                $value = deserialize($product[$attribute]);
+
+                if (\is_array($value)) {
+                    $update[$attribute] = implode(',', $value);
+                }
+            }
+
+            if (empty($update)) {
+                continue;
+            }
+
+            Database::getInstance()->prepare("UPDATE tl_iso_product %s WHERE id=?")->set($update)->execute($product['id']);
+        }
+    }
+}