diff --git a/Build/phpstan-baseline.neon b/Build/phpstan-baseline.neon
index e244ca64..2c4057f4 100644
--- a/Build/phpstan-baseline.neon
+++ b/Build/phpstan-baseline.neon
@@ -5,26 +5,6 @@ parameters:
 			count: 1
 			path: ../Classes/Controller/Cart/OrderController.php
 
-		-
-			message: "#^Deprecated in PHP 8\\.0\\: Required parameter \\$price follows optional parameter \\$beVariant\\.$#"
-			count: 1
-			path: ../Classes/Domain/Model/Cart/BeVariant.php
-
-		-
-			message: "#^Deprecated in PHP 8\\.0\\: Required parameter \\$priceCalcMethod follows optional parameter \\$beVariant\\.$#"
-			count: 1
-			path: ../Classes/Domain/Model/Cart/BeVariant.php
-
-		-
-			message: "#^Deprecated in PHP 8\\.0\\: Required parameter \\$sku follows optional parameter \\$beVariant\\.$#"
-			count: 1
-			path: ../Classes/Domain/Model/Cart/BeVariant.php
-
-		-
-			message: "#^Deprecated in PHP 8\\.1\\: Required parameter \\$title follows optional parameter \\$beVariant\\.$#"
-			count: 1
-			path: ../Classes/Domain/Model/Cart/BeVariant.php
-
 		-
 			message: "#^Call to an undefined method Extcode\\\\Cart\\\\Domain\\\\Model\\\\Cart\\\\CartCouponInterface\\:\\:getTaxClass\\(\\)\\.$#"
 			count: 2
diff --git a/Classes/Domain/Model/Cart/BeVariant.php b/Classes/Domain/Model/Cart/BeVariant.php
index a1f47162..0fff53a3 100644
--- a/Classes/Domain/Model/Cart/BeVariant.php
+++ b/Classes/Domain/Model/Cart/BeVariant.php
@@ -13,10 +13,6 @@
 
 class BeVariant
 {
-    protected ?Product $product = null;
-
-    protected ?BeVariant $parentBeVariant = null;
-
     protected string $titleDelimiter = ' - ';
 
     protected string $skuDelimiter = '-';
@@ -45,30 +41,13 @@ class BeVariant
 
     public function __construct(
         protected string $id,
-        ?Product $product = null,
-        ?self $beVariant = null,
+        protected self|Product $parent,
         protected string $title,
         protected string $sku,
         protected int $priceCalcMethod,
         protected float $price,
         protected int $quantity = 0
     ) {
-        if ($product === null && $beVariant === null) {
-            throw new \InvalidArgumentException();
-        }
-
-        if ($product != null && $beVariant != null) {
-            throw new \InvalidArgumentException();
-        }
-
-        if ($product !== null) {
-            $this->product = $product;
-        }
-
-        if ($beVariant !== null) {
-            $this->parentBeVariant = $beVariant;
-        }
-
         $this->reCalc();
     }
 
@@ -102,36 +81,28 @@ public function toArray(): array
         return $variantArr;
     }
 
-    public function getProduct(): ?Product
+    public function getParent(): self|Product
     {
-        return $this->product;
+        return $this->parent;
     }
 
-    public function setProduct(Product $product): void
+    public function setParent(self|Product $parent): void
     {
-        $this->product = $product;
+        $this->parent = $parent;
     }
 
-    public function getParentBeVariant(): ?self
+    public function getProduct(): Product
     {
-        return $this->parentBeVariant;
-    }
+        if ($this->parent instanceof Product) {
+            return $this->parent;
+        }
 
-    public function setParentBeVariant(self $parentBeVariant): void
-    {
-        $this->parentBeVariant = $parentBeVariant;
+        return $this->parent->getProduct();
     }
 
     public function isNetPrice(): bool
     {
-        if ($this->getParentBeVariant()) {
-            return $this->getParentBeVariant()->isNetPrice();
-        }
-        if ($this->getProduct()) {
-            return $this->getProduct()->isNetPrice();
-        }
-
-        return false;
+        return $this->parent->isNetPrice();
     }
 
     public function getId(): string
@@ -158,10 +129,10 @@ public function getCompleteTitle(): string
     {
         $title = '';
 
-        if ($this->getParentBeVariant()) {
-            $title = $this->getParentBeVariant()->getCompleteTitle();
-        } elseif ($this->getProduct()) {
-            $title = $this->getProduct()->getTitle();
+        if ($this->parent instanceof self) {
+            $title = $this->parent->getCompleteTitle();
+        } elseif ($this->parent instanceof Product) {
+            $title = $this->parent->getTitle();
         }
 
         if ($this->isFeVariant) {
@@ -178,8 +149,8 @@ public function getCompleteTitleWithoutProduct(): string
         $title = '';
         $titleDelimiter = '';
 
-        if ($this->getParentBeVariant()) {
-            $title = $this->getParentBeVariant()->getCompleteTitleWithoutProduct();
+        if ($this->parent instanceof self) {
+            $title = $this->parent->getCompleteTitleWithoutProduct();
             $titleDelimiter = $this->titleDelimiter;
         }
 
@@ -244,12 +215,12 @@ public function getPriceCalculated(): float
     {
         $price = $this->getBestPrice();
 
-        if ($this->getParentBeVariant()) {
-            $parentPrice = $this->getParentBeVariant()->getBestPrice();
-        } elseif ($this->getProduct()) {
-            $parentPrice = $this->getProduct()->getBestPrice($this->getQuantity());
+        if ($this->parent instanceof self) {
+            $parentPrice = $this->parent->getBestPrice();
+        } elseif ($this->parent instanceof Product) {
+            $parentPrice = $this->parent->getBestPrice($this->getQuantity());
         } else {
-            $parentPrice = 0;
+            $parentPrice = 0.0;
         }
 
         if ($this->priceCalcMethod === 0) {
@@ -285,15 +256,11 @@ public function getParentPrice(): float
             return 0.0;
         }
 
-        if ($this->getParentBeVariant()) {
-            return $this->getParentBeVariant()->getBestPrice();
+        if ($this->parent instanceof self) {
+            return $this->parent->getBestPrice();
         }
 
-        if ($this->getProduct()) {
-            return $this->getProduct()->getBestPrice($this->getQuantity());
-        }
-
-        return 0.0;
+        return $this->parent->getBestPrice($this->getQuantity());
     }
 
     public function setPrice(float $price): void
@@ -332,10 +299,10 @@ public function getCompleteSku(): string
     {
         $sku = '';
 
-        if ($this->getParentBeVariant()) {
-            $sku = $this->getParentBeVariant()->getCompleteSku();
-        } elseif ($this->getProduct()) {
-            $sku = $this->getProduct()->getSku();
+        if ($this->parent instanceof self) {
+            $sku = $this->parent->getCompleteSku();
+        } elseif ($this->parent instanceof Product) {
+            $sku = $this->parent->getSku();
         }
 
         if ($this->isFeVariant) {
@@ -353,8 +320,8 @@ public function getCompleteSkuWithoutProduct(): string
 
         $skuDelimiter = '';
 
-        if ($this->getParentBeVariant()) {
-            $sku = $this->getParentBeVariant()->getCompleteSkuWithoutProduct();
+        if ($this->parent instanceof self) {
+            $sku = $this->parent->getCompleteSkuWithoutProduct();
             $skuDelimiter = $this->titleDelimiter;
         }
 
@@ -416,14 +383,7 @@ public function getTax(): float
 
     public function getTaxClass(): ?TaxClass
     {
-        if ($this->getParentBeVariant()) {
-            return $this->getParentBeVariant()->getTaxClass();
-        }
-        if ($this->getProduct()) {
-            return $this->getProduct()->getTaxClass();
-        }
-
-        return null;
+        return $this->parent->getTaxClass();
     }
 
     public function setQuantity(int $newQuantity): void
diff --git a/Classes/Domain/Model/Cart/Product.php b/Classes/Domain/Model/Cart/Product.php
index c1f5b65c..9791896c 100644
--- a/Classes/Domain/Model/Cart/Product.php
+++ b/Classes/Domain/Model/Cart/Product.php
@@ -130,7 +130,7 @@ public function addBeVariant(BeVariant $newVariant): void
                 $variant->setQuantity($newQuantity);
             }
         } else {
-            $newVariant->setProduct($this);
+            $newVariant->setParent($this);
             $this->beVariants[$newVariantsId] = $newVariant;
         }
 
diff --git a/Classes/EventListener/Order/Create/PersistOrder/Products.php b/Classes/EventListener/Order/Create/PersistOrder/Products.php
index bb0f06ac..b23992ff 100644
--- a/Classes/EventListener/Order/Create/PersistOrder/Products.php
+++ b/Classes/EventListener/Order/Create/PersistOrder/Products.php
@@ -141,20 +141,7 @@ protected function addVariantsOfVariant(BeVariant $variant, int $level): void
 
     protected function addBeVariant(BeVariant $variant, int $level): void
     {
-        $variantInner = $variant;
-        for ($count = $level; $count > 0; $count--) {
-            if ($count > 1) {
-                $variantInner = $variantInner->getParentBeVariant();
-            } else {
-                $cartProduct = $variantInner->getProduct();
-            }
-        }
-        unset($variantInner);
-
-        if (!isset($cartProduct)) {
-            // ToDo Add Error Message
-            return;
-        }
+        $cartProduct = $variant->getProduct();
 
         $orderProduct = GeneralUtility::makeInstance(
             \Extcode\Cart\Domain\Model\Order\Product::class
@@ -193,11 +180,7 @@ protected function addBeVariant(BeVariant $variant, int $level): void
 
             $orderProduct->addProductAdditional($orderProductAdditional);
 
-            if ($count > 1) {
-                $variantInner = $variantInner->getParentBeVariant();
-            } else {
-                $cartProduct = $variantInner->getProduct();
-            }
+            $variantInner = $variantInner->getParent();
         }
         unset($variantInner);
 
diff --git a/Classes/ViewHelpers/FieldNameViewHelper.php b/Classes/ViewHelpers/FieldNameViewHelper.php
index 6e2475bd..b4593272 100644
--- a/Classes/ViewHelpers/FieldNameViewHelper.php
+++ b/Classes/ViewHelpers/FieldNameViewHelper.php
@@ -55,11 +55,12 @@ protected function getVariantFieldName(BeVariant $variant): string
     {
         $fieldName = '';
 
-        if ($variant->getParentBeVariant()) {
-            $fieldName .= $this->getVariantFieldName($variant->getParentBeVariant());
+        if ($variant->getParent() instanceof BeVariant) {
+            $fieldName .= $this->getVariantFieldName($variant->getParent());
         }
-        if ($variant->getProduct()) {
-            $fieldName .= '[' . $variant->getProduct()->getId() . ']';
+
+        if ($variant->getParent() instanceof Product) {
+            $fieldName .= '[' . $variant->getParent()->getId() . ']';
         }
 
         $fieldName .= '[' . $variant->getId() . ']';
diff --git a/Documentation/Changelog/10.0/Breaking-611-ChangePhpDependency.rst b/Documentation/Changelog/10.0/Breaking-611-ChangePhpDependency.rst
new file mode 100644
index 00000000..eea1c0db
--- /dev/null
+++ b/Documentation/Changelog/10.0/Breaking-611-ChangePhpDependency.rst
@@ -0,0 +1,33 @@
+.. include:: ../../Includes.rst.txt
+
+=================================================
+Breaking: #611 - Change BeVariant Parent Handling
+=================================================
+
+See `Issue 611 <https://github.com/extcode/cart/issues/611>`__
+
+Description
+===========
+
+Previously, a `BeVariant` had either another `BeVariant` or a `Product` as its parent element. These were passed in the
+constructor method.
+
+Thanks to PHP's union types, this can now be resolved. A `BeVariant` now has a `$parent` that is either of type
+`BeVariant` or of type `Product`.
+
+The individual methods have been adapted accordingly and it is checked of which class `$parent` is an instance. In some
+cases, the case differentiation could be omitted completely.
+
+Affected Installations
+======================
+
+All product extensions that use their own `BeVariant` in the products are affected. The provided extensions
+extcode/cart-products and extcode/cart-events will be adapted accordingly.
+
+Migration
+=========
+
+If a custom product extension is used, the constructor must be adapted accordingly. Furthermore, a few
+methods in `BeVariant` have been replaced or their behavior adapted.
+
+.. index:: API
diff --git a/Documentation/Changelog/10.0/Index.rst b/Documentation/Changelog/10.0/Index.rst
new file mode 100644
index 00000000..f1afa74d
--- /dev/null
+++ b/Documentation/Changelog/10.0/Index.rst
@@ -0,0 +1,20 @@
+.. include:: ../../Includes.rst.txt
+
+10.0 Changes
+============
+
+**Table of contents**
+
+.. contents::
+   :local:
+   :depth: 1
+
+Breaking
+--------
+
+.. toctree::
+   :maxdepth: 1
+   :titlesonly:
+   :glob:
+
+   Breaking-*
diff --git a/Documentation/Changelog/Index.rst b/Documentation/Changelog/Index.rst
index 6d026dc3..df6a0063 100644
--- a/Documentation/Changelog/Index.rst
+++ b/Documentation/Changelog/Index.rst
@@ -10,6 +10,7 @@ ChangeLog
    :maxdepth: 5
    :titlesonly:
 
+   10.0/Index
    9.4/Index
    9.3/Index
    9.1/Index
diff --git a/Documentation/guides.xml b/Documentation/guides.xml
index f95211ce..39dfb9f7 100644
--- a/Documentation/guides.xml
+++ b/Documentation/guides.xml
@@ -11,8 +11,8 @@
                interlink-shortcode="extcode/cart"
     />
     <project title="Cart"
-             release="9.4.1"
-             version="9.4"
+             release="10.0.0"
+             version="10.0"
              copyright="2018 - 2024"
     />
     <inventory id="t3tsref" url="https://docs.typo3.org/typo3cms/TyposcriptReference/"/>
diff --git a/README.md b/README.md
index 4e45ee32..7ca1f648 100644
--- a/README.md
+++ b/README.md
@@ -45,17 +45,7 @@ Sometimes minor versions also result in minor adjustments to own templates or co
 
 ## 3.1 Compatibility and supported Versions
 
-| Cart   | TYPO3      | PHP       | Support/Development                  |
-|--------|------------|-----------|--------------------------------------|
-| 9.x.x  | 12.4       | 8.1 - 8.4 | Features, Bugfixes, Security Updates |
-| 8.x.x  | 10.4, 11.5 | 7.2+      | Features, Bugfixes, Security Updates |
-| 7.x.x  | 10.4       | 7.2 - 7.4 | Security Updates                     |
-| 6.x.x  | 9.5        | 7.2 - 7.4 |                                      |
-| 5.x.x  | 8.7        | 7.0 - 7.4 |                                      |
-| 4.x.x  | 7.6 - 8.7  | 5.6 - 7.2 |                                      |
-| 3.x.x  | 6.2 - 8.7  | 5.6 - 7.0 |                                      |
-| 2.x.x  |            |           |                                      |
-| 1.x.x  |            |           |                                      |
+Please refer to the current [README](https://github.com/extcode/cart/blob/main/README.md#31-compatibility-and-supported-versions).
 
 If you need extended support for features and bug fixes outside of the currently supported versions,
 we are happy to offer paid services.
diff --git a/Tests/Unit/Domain/Model/Cart/BeVariantTest.php b/Tests/Unit/Domain/Model/Cart/BeVariantTest.php
index dd255dde..70734a85 100644
--- a/Tests/Unit/Domain/Model/Cart/BeVariantTest.php
+++ b/Tests/Unit/Domain/Model/Cart/BeVariantTest.php
@@ -68,7 +68,6 @@ public function setUp(): void
         $this->beVariant = new BeVariant(
             $this->id,
             $this->product,
-            null,
             $this->title,
             $this->sku,
             $this->priceCalcMethod,
@@ -181,40 +180,6 @@ public function getQuantityReturnsQuantitySetByConstructor(): void
         );
     }
 
-    #[Test]
-    public function constructVariantWithoutCartProductOrVariantThrowsInvalidArgumentException(): void
-    {
-        $this->expectException(\InvalidArgumentException::class);
-
-        new BeVariant(
-            $this->id,
-            null,
-            null,
-            $this->sku,
-            $this->title,
-            $this->priceCalcMethod,
-            $this->price,
-            $this->quantity
-        );
-    }
-
-    #[Test]
-    public function constructVariantWithCartProductAndVariantThrowsInvalidArgumentException(): void
-    {
-        $this->expectException(\InvalidArgumentException::class);
-
-        new BeVariant(
-            $this->id,
-            $this->product,
-            $this->beVariant,
-            $this->sku,
-            $this->title,
-            $this->priceCalcMethod,
-            $this->price,
-            $this->quantity
-        );
-    }
-
     #[Test]
     public function constructWithoutTitleThrowsException(): void
     {
@@ -224,7 +189,6 @@ public function constructWithoutTitleThrowsException(): void
             1,
             $this->product,
             null,
-            null,
             'test-variant-sku',
             0,
             1.0,
@@ -240,7 +204,6 @@ public function constructWithoutSkuThrowsException(): void
         new BeVariant(
             1,
             $this->product,
-            null,
             'Test Variant',
             null,
             0,
@@ -257,7 +220,6 @@ public function constructWithoutQuantityThrowsException(): void
         new BeVariant(
             1,
             $this->product,
-            null,
             'Test Variant',
             'test-variant-sku',
             0,
@@ -448,7 +410,6 @@ public function getParentPriceRespectsTheQuantityDiscountsOfProductsForEachVaria
         $beVariant1 = new BeVariant(
             '1',
             $this->product,
-            null,
             $title,
             $sku,
             $priceCalcMethod,
@@ -460,7 +421,6 @@ public function getParentPriceRespectsTheQuantityDiscountsOfProductsForEachVaria
         $beVariant2 = new BeVariant(
             '2',
             $this->product,
-            null,
             $title,
             $sku,
             $priceCalcMethod,
@@ -472,7 +432,6 @@ public function getParentPriceRespectsTheQuantityDiscountsOfProductsForEachVaria
         $beVariant3 = new BeVariant(
             '3',
             $this->product,
-            null,
             $title,
             $sku,
             $priceCalcMethod,
diff --git a/ext_emconf.php b/ext_emconf.php
index 47470a61..b9e29680 100644
--- a/ext_emconf.php
+++ b/ext_emconf.php
@@ -4,7 +4,7 @@
     'title' => 'Cart',
     'description' => 'Shopping Cart(s) for TYPO3',
     'category' => 'plugin',
-    'version' => '9.4.1',
+    'version' => '10.0.0',
     'state' => 'stable',
     'author' => 'Daniel Gohlke',
     'author_email' => 'ext@extco.de',