diff --git a/README.md b/README.md
index 47b0a93..cdea5ee 100644
--- a/README.md
+++ b/README.md
@@ -6,7 +6,7 @@
 
 ## Requirements
 
-* SilverStripe 3.0
+* SilverStripe 4.0
 
 ## Documentation
 
diff --git a/_config.php b/_config.php
index a4abe2d..b3d9bbc 100644
--- a/_config.php
+++ b/_config.php
@@ -1,2 +1 @@
 <?php
-
diff --git a/_config/routes.yml b/_config/routes.yml
index fee5b88..0b0c4ce 100644
--- a/_config/routes.yml
+++ b/_config/routes.yml
@@ -1,6 +1,6 @@
 ---
 Name: googleshoppingfeedroutes
 ---
-Director:
+SilverStripe\Control\Director:
   rules:
-    'shoppingfeed.xml': 'GoogleShoppingFeedController'
+    'shoppingfeed.xml': 'ilateral\SilverStripe\GoogleShoppingFeed\Control\GoogleShoppingFeedController'
diff --git a/_config/shoppingfeed.yml b/_config/shoppingfeed.yml
index 684f6c5..ef03a0a 100644
--- a/_config/shoppingfeed.yml
+++ b/_config/shoppingfeed.yml
@@ -13,5 +13,5 @@ After: '#catalogueconfig'
 ---
 SilverCommerce\CatalogueAdmin\Model\CatalogueProduct:
   extensions:
-    ilateral\SilverStripe\GoogleShoppingFeed\extensions\Extension
+    - ilateral\SilverStripe\GoogleShoppingFeed\Extensions\Extension
   
\ No newline at end of file
diff --git a/templates/xml-sitemap.xsl b/client/dist/xsl/xml-sitemap.xsl
similarity index 100%
rename from templates/xml-sitemap.xsl
rename to client/dist/xsl/xml-sitemap.xsl
diff --git a/src/.upgrade.yml b/src/.upgrade.yml
index c76104f..c446c68 100644
--- a/src/.upgrade.yml
+++ b/src/.upgrade.yml
@@ -1,5 +1,5 @@
 mappings:
-  GoogleShoppingFeedExtension: ilateral\SilverStripe\GoogleShoppingFeed\extensions\Extension
-  GoogleProductCategory: ilateral\SilverStripe\GoogleShoppingFeed\model\GoogleProductCategory
+  GoogleShoppingFeedExtension: ilateral\SilverStripe\GoogleShoppingFeed\Extensions\Extension
+  GoogleProductCategory: ilateral\SilverStripe\GoogleShoppingFeed\Model\GoogleProductCategory
   GoogleShoppingFeed: ilateral\SilverStripe\GoogleShoppingFeed\GoogleShoppingFeed
-  GoogleShoppingFeedController: ilateral\SilverStripe\GoogleShoppingFeed\controllers\GoogleShoppingFeedController
+  GoogleShoppingFeedController: ilateral\SilverStripe\GoogleShoppingFeed\Control\GoogleShoppingFeedController
diff --git a/src/controllers/GoogleShoppingFeedController.php b/src/Control/GoogleShoppingFeedController.php
similarity index 93%
rename from src/controllers/GoogleShoppingFeedController.php
rename to src/Control/GoogleShoppingFeedController.php
index 4a6c76b..efc8053 100644
--- a/src/controllers/GoogleShoppingFeedController.php
+++ b/src/Control/GoogleShoppingFeedController.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace ilateral\SilverStripe\GoogleShoppingFeed\controllers;
+namespace ilateral\SilverStripe\GoogleShoppingFeed\Control;
 
 use NumberFormatter;
 use SilverStripe\i18n\i18n;
@@ -49,7 +49,7 @@ public function index()
                 'noindex'
             );
 
-            $items = GoogleShoppingFeed::get_items();
+            $items = GoogleShoppingFeed::getItems();
             
             $currency = new NumberFormatter(i18n::get_locale(), NumberFormatter::CURRENCY);
             
diff --git a/src/extensions/Extension.php b/src/Extensions/Extension.php
similarity index 95%
rename from src/extensions/Extension.php
rename to src/Extensions/Extension.php
index 489fa99..4844fae 100644
--- a/src/extensions/Extension.php
+++ b/src/Extensions/Extension.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace ilateral\SilverStripe\GoogleShoppingFeed\extensions;
+namespace ilateral\SilverStripe\GoogleShoppingFeed\Extensions;
 
 use SilverStripe\Assets\Image;
 use SilverStripe\ORM\ArrayList;
@@ -14,6 +14,7 @@
 use SilverStripe\Forms\ToggleCompositeField;
 use SilverStripe\AssetAdmin\Forms\UploadField;
 use TractorCow\AutoComplete\AutoCompleteField;
+use ilateral\SilverStripe\GoogleShoppingFeed\Model\GoogleProductCategory;
 
 
 class Extension extends DataExtension
@@ -32,9 +33,9 @@ class Extension extends DataExtension
     ];
 
     private static $has_one = [
-        "ShoppingPrimaryImage"    => "Image",
-        "ShoppingAdditionalImage" => "Image",
-        "GoogleProductCategory" => "GoogleProductCategory"
+        "ShoppingPrimaryImage"    => Image::class,
+        "ShoppingAdditionalImage" => Image::class,
+        "GoogleProductCategory" => GoogleProductCategory::class
     ];
 
     /**
@@ -172,9 +173,7 @@ public function addCMSFieldsToTabset($tabset)
                     'GoogleProductCategoryID',
                     $this->owner->fieldLabel("GoogleProductCategory"),
                     '',
-                    null,
-                    null,
-                    'GoogleProductCategory',
+                    GoogleProductCategory::class,
                     'Title'
                 ),
                 UploadField::create("ShoppingPrimaryImage")
@@ -202,8 +201,6 @@ public function hasCMSSettingsFields()
      */
     public function updateSettingsFields(FieldList $fields)
     {
-        var_dump("i'm here!");
-        exit;
         if($this->owner->hasCMSSettingsFields()) {
             $tabset = $fields->findOrMakeTab('Root.Settings');
 
@@ -221,8 +218,6 @@ public function updateSettingsFields(FieldList $fields)
      */
     public function updateCMSFields(FieldList $fields)
     {
-        var_dump("i'm here!");
-        exit;
         if (!$this->owner->hasCMSSettingsFields()) {
             $tabset = $fields->findOrMakeTab('Root.Settings');
 
diff --git a/src/GoogleShoppingFeed.php b/src/GoogleShoppingFeed.php
index 842eea6..c547826 100644
--- a/src/GoogleShoppingFeed.php
+++ b/src/GoogleShoppingFeed.php
@@ -2,6 +2,7 @@
 
 namespace ilateral\SilverStripe\GoogleShoppingFeed;
 
+use Product;
 use SilverStripe\ORM\DataList;
 use SilverStripe\ORM\ArrayList;
 use SilverStripe\Core\Config\Config;
@@ -66,7 +67,7 @@ class GoogleShoppingFeed
     public static function register_dataobject($className)
     {
         if (!self::is_registered($className)) {
-            $className::add_extension('GoogleShoppingFeedExtension');
+            $className::add_extension(Extension::class);
             
             self::$dataobjects[] = $className;
         }
@@ -130,20 +131,20 @@ public static function clear_registered_dataobjects()
      *
      * @return ArrayList
      */
-    public static function get_items()
+    public static function getItems()
     {
         $output = new ArrayList();
-        $search_filter =  Config::inst()->get('GoogleShoppingFeed', 'use_show_in_search');
-        $disabled_filter =  Config::inst()->get('GoogleShoppingFeed', 'use_disabled');
+        $search_filter =  Config::inst()->get(__CLASS__, 'use_show_in_search');
+        $disabled_filter =  Config::inst()->get(__CLASS__, 'use_disabled');
         $filter = array();
 
         // todo migrate to extension hook or DI point for other modules to 
         foreach (self::$dataobjects as $class) {
-            if ($class == "SiteTree") {
+            if ($class == SiteTree::class) {
                 $search_filter = ($search_filter) ? "\"ShowInSearch\" = 1" : "";
 
                 $instances = Versioned::get_by_stage('SiteTree', 'Live', $search_filter);
-            } elseif ($class == "Product") {
+            } elseif ($class == Product::class) {
                 $instances = $class::get();
                 
                 if ($disabled_filter) {
@@ -164,6 +165,20 @@ public static function get_items()
 
         return $output;
     }
+
+    /**
+     * Static interface to instance level ->getItems() for backward compatibility.
+     *
+     * @param string
+     * @param int
+     *
+     * @return ArrayList
+     * @deprecated Please create an instance and call ->getSitemaps() instead.
+     */
+    public static function get_items()
+    {
+        return static::inst()->getItems();
+    }
     
     /**
      * Returns the string frequency of edits for a particular dataobject class.
@@ -191,6 +206,6 @@ public static function get_frequency_for_class($class)
      */
     public static function enabled()
     {
-        return (Config::inst()->get('GoogleShoppingFeed', 'enabled', Config::INHERITED));
+        return (Config::inst()->get(self::class, 'enabled'));
     }
 }
diff --git a/src/model/GoogleProductCategory.php b/src/Model/GoogleProductCategory.php
similarity index 92%
rename from src/model/GoogleProductCategory.php
rename to src/Model/GoogleProductCategory.php
index 88a7134..508368f 100644
--- a/src/model/GoogleProductCategory.php
+++ b/src/Model/GoogleProductCategory.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace ilateral\SilverStripe\GoogleShoppingFeed\model;
+namespace ilateral\SilverStripe\GoogleShoppingFeed\Model;
 
 use SilverStripe\ORM\DB;
 use SilverStripe\ORM\DataObject;
@@ -56,7 +56,7 @@ public function getGoogleCategories()
     {
         // Get a list of Google Categories from the 
         // product file.
-        $file = BASE_PATH . "/googleshoppingfeed/thirdparty/google_product_taxonomy.txt";
+        $file = __DIR__ . "../../thirdparty/google_product_taxonomy.txt";
         $fopen = fopen($file, 'r');
         $fread = fread($fopen, filesize($file));
         fclose($fopen);
diff --git a/templates/GoogleShoppingFeedController.ss b/templates/ilateral/SilverStripe/GoogleShoppingFeed/Control/GoogleShoppingFeedController.ss
similarity index 100%
rename from templates/GoogleShoppingFeedController.ss
rename to templates/ilateral/SilverStripe/GoogleShoppingFeed/Control/GoogleShoppingFeedController.ss
diff --git a/tests/GoogleShoppingFeedTest.php b/tests/GoogleShoppingFeedTest.php
index a3d4f62..ca36564 100644
--- a/tests/GoogleShoppingFeedTest.php
+++ b/tests/GoogleShoppingFeedTest.php
@@ -33,7 +33,7 @@ public function testGetItems()
     {
         GoogleShoppingFeed::register_dataobject("GoogleShoppingFeedTest_Product", '');
 
-        $items = GoogleShoppingFeed::get_items('GoogleShoppingFeedTest_Product', 1);
+        $items = GoogleShoppingFeed::getItems('GoogleShoppingFeedTest_Product', 1);
         $this->assertEquals(3, $items->count());
     }