diff --git a/README.md b/README.md
index 7df6280..6fa80ce 100644
--- a/README.md
+++ b/README.md
@@ -8,7 +8,7 @@ A front-end control for sorting SilverStripe lists easily. The aim of this modul
 
 ## Requirements
 
- * SilverStripe 4+ or 5+
+ * SilverStripe ^6
 
 ## Usage
 
@@ -21,10 +21,10 @@ public function getSorter(){
 		'Title', //DB field name only
 		'Popularity' => 'Popularity DESC', //map title to sort sql
 		'Price' => ['BasePrice' => 'ASC'], //map title to data list sort
-		ListSorter_Option::create('Age', ['Created' => 'DESC'], //object
-			ListSorter_Option::create('Age', ['Created' => 'ASC']) //reverse
-		)
-	;
+		ListSorterOption::create('Age', ['Created' => 'DESC']), //object
+		ListSorterOption::create('Age', ['Created' => 'ASC']) //reverse
+    ];
+
 	return ListSorter::create($this->request,$sorts);
 }
 ```
diff --git a/composer.json b/composer.json
index 3508691..7d0e75f 100644
--- a/composer.json
+++ b/composer.json
@@ -13,7 +13,7 @@
         }
     ],
     "require": {
-        "silverstripe/framework": "^4.0 | ^5.0"
+        "silverstripe/framework": "^6"
     },
     "extra": {
          "branch-alias": {
diff --git a/src/ListSorter.php b/src/ListSorter.php
index b10a734..e3b010b 100644
--- a/src/ListSorter.php
+++ b/src/ListSorter.php
@@ -1,19 +1,23 @@
 <?php
 
+declare(strict_types=1);
+
 namespace SilverShop\ListSorter;
 
+use SilverStripe\Model\List\ArrayList;
+use SilverStripe\Model\ModelData;
 use SilverStripe\Control\HTTPRequest;
-use SilverStripe\ORM\ArrayList;
 use SilverStripe\ORM\DataList;
-use SilverStripe\View\ViewableData;
 
 /**
  * Control for front-end sorting manipulations
  */
-class ListSorter extends ViewableData
+class ListSorter extends ModelData
 {
-    private $request;
-    private $sortOptions = [];
+    private HTTPRequest $request;
+
+    private array $sortOptions = [];
+
     private $current;
 
     public function __construct(HTTPRequest $request, $options = null)
@@ -29,18 +33,19 @@ public function __construct(HTTPRequest $request, $options = null)
      *
      * @param array $options
      */
-    public function setSortOptions($options)
+    public function setSortOptions($options): void
     {
         $this->sortOptions = [];
         foreach ($options as $key => $value) {
             if (is_numeric($key)) {
                 $key = $value;
             }
+
             if ($value instanceof ListSorterOption) {
                 $this->addSortOption($value);
             } else {
                 $this->addSortOption(
-                    new ListSorterOption($key, $value)
+                    ListSorterOption::create($key, $value)
                 );
             }
         }
@@ -48,16 +53,15 @@ public function setSortOptions($options)
 
     /**
      * Add sort option, and set according to sort request param.
-     *
-     * @param ListSorterOption $option
      */
-    public function addSortOption(ListSorterOption $option)
+    public function addSortOption(ListSorterOption $option): void
     {
         $this->sortOptions[(string)$option] = $option;
         $requestparam = $this->request->getVar('sort');
         if ((string)$option === $requestparam) {
             $this->current = $option;
         }
+
         if ((string)$option->getReverseOption() === $requestparam) {
             $this->current = $option->getReverseOption();
         }
@@ -78,12 +82,12 @@ protected function getCurrentOption()
      *
      * @param $option
      */
-    public function setCurrentOption(ListSorterOption $option)
+    public function setCurrentOption(ListSorterOption $option): void
     {
         $this->current = $option;
     }
 
-    protected function isCurrent(ListSorterOption $option)
+    protected function isCurrent(ListSorterOption $option): bool
     {
         return $option === $this->getCurrentOption();
     }
@@ -99,8 +103,10 @@ public function getSorts()
                 if ($option->isReversable()) {
                     $option = $option->getReverseOption();
                 }
+
                 $option = $option->customise(['IsCurrent' => true]);
             }
+
             $sorts->push($option);
         }
 
@@ -116,7 +122,7 @@ public function getSorts()
     public function sortList($list)
     {
         if ($current = $this->getCurrentOption()) {
-            $list = $list->sort($current->getSortSet());
+            return $list->sort($current->getSortSet());
         }
 
         return $list;
diff --git a/src/ListSorterOption.php b/src/ListSorterOption.php
index 30c785b..616011e 100644
--- a/src/ListSorterOption.php
+++ b/src/ListSorterOption.php
@@ -1,19 +1,24 @@
 <?php
 
+declare(strict_types=1);
+
 namespace SilverShop\ListSorter;
 
+use SilverStripe\Model\ModelData;
 use SilverStripe\Control\HTTP;
-use SilverStripe\View\ViewableData;
 
 /**
  * Encapsulate sort option title, sorting SQL,
  * GET parameter key, and reverse option.
  */
-class ListSorterOption extends ViewableData
+class ListSorterOption extends ModelData
 {
     protected $title;
+
     protected $id;
+
     protected $sortSet;
+
     protected $reverseOption;
 
     public function __construct($title, $sortset, ListSorterOption $reverseOption = null)
@@ -21,7 +26,7 @@ public function __construct($title, $sortset, ListSorterOption $reverseOption =
         $this->title = $title;
         $this->setID($title);
         $this->sortSet = $sortset;
-        if ($reverseOption) {
+        if ($reverseOption instanceof \SilverShop\ListSorter\ListSorterOption) {
             $this->setReverseOption($reverseOption);
         }
     }
@@ -31,7 +36,7 @@ public function getTitle()
         return $this->title;
     }
 
-    public function setTitle($title)
+    public function setTitle($title): static
     {
         $this->title = $title;
         return $this;
@@ -42,15 +47,17 @@ public function getSortSet()
         return $this->sortSet;
     }
 
-    public function setReverseOption(ListSorterOption $option)
+    public function setReverseOption(ListSorterOption $option): static
     {
         $this->reverseOption = $option;
         if (!$option->isReversable()) {
             if ($this->getID() === $option->getID()) {
-                $option->setID((string)$option . "_rev");
+                $option->setID($option . "_rev");
             }
+
             $option->setReverseOption($this);
         }
+
         return $this;
     }
 
@@ -59,12 +66,12 @@ public function getReverseOption()
         return $this->reverseOption;
     }
 
-    public function isReversable()
+    public function isReversable(): bool
     {
         return (bool)$this->reverseOption;
     }
 
-    public function setID($id)
+    public function setID($id): static
     {
         $this->id = strtolower(trim($id));
         return $this;
@@ -75,7 +82,7 @@ public function getID()
         return $this->id;
     }
 
-    public function __toString()
+    public function __toString(): string
     {
         return $this->id;
     }
@@ -93,9 +100,8 @@ public function getLink()
      */
     private function generateLink($id)
     {
-        $url = Http::setGetVar('sort', $id, null, '&');
         //TODO: strip "start" pagination parameter,
         //as most users won't want to remain on paginated page when sorting
-        return $url;
+        return Http::setGetVar('sort', $id, null, '&');
     }
 }
diff --git a/tests/php/ListSorterTest.php b/tests/php/ListSorterTest.php
index 5ce3288..8412b51 100644
--- a/tests/php/ListSorterTest.php
+++ b/tests/php/ListSorterTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace SilverShop\ListSorter\Tests;
 
 use SilverStripe\Control\HTTPRequest;
@@ -8,7 +10,7 @@
 use SilverShop\ListSorter\ListSorterOption;
 use SilverShop\ListSorter\Tests\Stubs\ListSorterPerson;
 
-class ListSorterTest extends SapphireTest
+final class ListSorterTest extends SapphireTest
 {
     protected static $fixture_file = 'fixture.yaml';
 
@@ -16,7 +18,7 @@ class ListSorterTest extends SapphireTest
         ListSorterPerson::class
     ];
 
-    public function testSorting()
+    public function testSorting(): void
     {
         $list = ListSorterPerson::get();
 
@@ -74,7 +76,7 @@ public function testSorting()
         );
     }
 
-    public function testListSorterOption()
+    public function testListSorterOption(): void
     {
         $option = ListSorterOption::create(
             'Age Title',
@@ -86,13 +88,13 @@ public function testListSorterOption()
         $this->assertEquals('age title', $option->getID());
         $this->assertEquals('age title', (string)$option);
         $this->assertTrue($option->isReversable());
-        $this->assertEquals('/?colors=always&url=%2F&sort=age+title', $option->getLink());
+        $this->assertEquals('/?url=%2F&sort=age+title', $option->getLink());
 
         $reverse = $option->getReverseOption();
         $this->assertEquals('Age Title', $reverse->getTitle());
         $this->assertEquals('age title_rev', $reverse->getID());
         $this->assertEquals('age title_rev', (string)$reverse);
         $this->assertTrue($reverse->isReversable());
-        $this->assertEquals('/?colors=always&url=%2F&sort=age+title_rev', $reverse->getLink());
+        $this->assertEquals('/?url=%2F&sort=age+title_rev', $reverse->getLink());
     }
 }
diff --git a/tests/php/Stubs/ListSorterPerson.php b/tests/php/Stubs/ListSorterPerson.php
index e939029..6c1e7a2 100644
--- a/tests/php/Stubs/ListSorterPerson.php
+++ b/tests/php/Stubs/ListSorterPerson.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace SilverShop\ListSorter\Tests\Stubs;
 
 use SilverStripe\Dev\TestOnly;
@@ -7,7 +9,9 @@
 
 class ListSorterPerson extends DataObject implements TestOnly
 {
-    private static $db = [
+    private static string $table_name = 'ListSorterPerson';
+
+    private static array $db = [
         'Title' => 'Varchar',
         'Age' => 'Int'
     ];