diff --git a/commerce_quote_cart.info.yml b/commerce_quote_cart.info.yml
index 36ca473..3e55c54 100644
--- a/commerce_quote_cart.info.yml
+++ b/commerce_quote_cart.info.yml
@@ -3,7 +3,12 @@ type: module
 description: 'Supports quote items for Drupal Commerce.'
 version: 8.x-1.x
 core: 8.x
+core_version_requirement: ^8 || ^9
 package: Commerce
 dependencies:
   - commerce_cart
+  - commerce_checkout
+  - commerce_order
   - commerce_product
+  - commerce_shipping
+  - hook_event_dispatcher
diff --git a/commerce_quote_cart.module b/commerce_quote_cart.module
index 61fb9a3..ebeafff 100644
--- a/commerce_quote_cart.module
+++ b/commerce_quote_cart.module
@@ -1,9 +1,11 @@
 <?php
 
 use Drupal\commerce\PurchasableEntityInterface;
+use Drupal\Core\Field\BaseFieldDefinition;
 use Drupal\commerce_quote_cart\QuoteCartHelper;
 use Drupal\commerce_product\Entity\ProductInterface;
 use Drupal\Core\Entity\FieldableEntityInterface;
+use Drupal\Core\Entity\EntityTypeInterface;
 use Drupal\Core\Form\FormStateInterface;
 
 /**
@@ -73,7 +75,7 @@ function commerce_quote_cart_submit_quote(array &$form, FormStateInterface $form
 
   /** @var \Drupal\commerce_order\Entity\OrderItemInterface $order_item */
   $order_item = $addToCartForm->getEntity();
-  $order_item->set('field_quote', ['value' => "1"]);
+  $order_item->set('quote', ['value' => "1"]);
 
   $addToCartForm->submitForm($form, $form_state);
 }
@@ -82,7 +84,7 @@ function commerce_quote_cart_submit_quote(array &$form, FormStateInterface $form
  * Implements hook_preprocess_block().
  */
 function commerce_quote_cart_preprocess_block(&$variables) {
-  if (in_array($variables['elements']['#id'], ['product_variations', 'product_variations_mobile'])) {
+  if (isset($variables['elements']['#id']) && in_array($variables['elements']['#id'], ['product_variations', 'product_variations_mobile'])) {
     $variables['label'] = commerce_quote_cart_block_label($variables);
   }
 
@@ -147,7 +149,7 @@ function commerce_quote_cart_block_label($variables) {
 }
 
 function commerce_quote_cart_product_is_purchasable(ProductInterface $product) {
-  $purchasableField = 'field_available_for_purchase';
+  $purchasableField = 'available_for_purchase';
   $variations = $product->getVariations();
 
   $purchasable = FALSE;
@@ -168,8 +170,8 @@ function commerce_quote_cart_preprocess_field(&$variables) {
     /** @var FieldableEntityInterface $entity */
     $entity = $variables['element']['#object'];
 
-    $purchasable = 'field_available_for_purchase';
-    $quotable = 'field_available_for_quote';
+    $purchasable = 'available_for_purchase';
+    $quotable = 'available_for_quote';
 
     if ($entity->hasField($purchasable) && !$entity->get($purchasable)->value) {
       if (isset($variables['items'][0])) {
@@ -242,3 +244,73 @@ function commerce_quote_cart_ga_push_add_alter(&$push_params, $type = GA_PUSH_TY
     $push_params['params'] = NULL;
   }
 }
+
+/**
+ * Implements hook_entity_base_field_info().
+ *
+ * Provides base fields for quote, purchase.
+ */
+function commerce_quote_cart_entity_base_field_info(EntityTypeInterface $entity_type) {
+  // Add base fields to commerce_order.
+  if ($entity_type->id() === 'commerce_order') {
+    $fields['quote'] = BaseFieldDefinition::create('boolean')
+      ->setLabel(t('Quote'))
+      ->setDisplayConfigurable('form', TRUE)
+      ->setDisplayOptions('form', [
+        'type' => 'boolean_checkbox',
+        'settings' => [
+          'display_label' => TRUE,
+        ]
+      ])
+      ->setDisplayConfigurable('view', TRUE);
+    $fields['purchase'] = BaseFieldDefinition::create('boolean')
+      ->setLabel(t('Purchase'))
+      ->setDisplayConfigurable('form', TRUE)
+      ->setDisplayOptions('form', [
+        'type' => 'boolean_checkbox',
+        'settings' => [
+          'display_label' => TRUE,
+        ]
+      ])
+      ->setDisplayConfigurable('view', TRUE);
+    return $fields;
+  }
+  // Add base field to commerce_order_item.
+  if ($entity_type->id() === 'commerce_order_item') {
+    $fields['quote'] = BaseFieldDefinition::create('boolean')
+      ->setLabel(t('Quote'))
+      ->setDisplayConfigurable('form', TRUE)
+      ->setDisplayOptions('form', [
+        'type' => 'boolean_checkbox',
+        'settings' => [
+          'display_label' => TRUE,
+        ]
+      ])
+      ->setDisplayConfigurable('view', TRUE);
+    return $fields;
+  }
+  // Add base fields to commerce_product_variation.
+  if ($entity_type->id() === 'commerce_product_variation') {
+    $fields['available_for_purchase'] = BaseFieldDefinition::create('boolean')
+      ->setLabel(t('Available for Purchase'))
+      ->setDisplayConfigurable('form', TRUE)
+      ->setDisplayOptions('form', [
+        'type' => 'boolean_checkbox',
+        'settings' => [
+          'display_label' => TRUE,
+        ]
+      ])
+      ->setDisplayConfigurable('view', TRUE);
+    $fields['available_for_quote'] = BaseFieldDefinition::create('boolean')
+      ->setLabel(t('Available for Quote'))
+      ->setDisplayConfigurable('form', TRUE)
+      ->setDisplayOptions('form', [
+        'type' => 'boolean_checkbox',
+        'settings' => [
+          'display_label' => TRUE,
+        ]
+      ])
+      ->setDisplayConfigurable('view', TRUE);
+    return $fields;
+  }
+}
diff --git a/src/EventSubscriber/CommerceQuoteCartSubscriber.php b/src/EventSubscriber/CommerceQuoteCartSubscriber.php
index b00f016..2a6a801 100644
--- a/src/EventSubscriber/CommerceQuoteCartSubscriber.php
+++ b/src/EventSubscriber/CommerceQuoteCartSubscriber.php
@@ -5,7 +5,6 @@
 use Drupal\commerce_cart\Event\CartEntityAddEvent;
 use Drupal\commerce_cart\Event\CartOrderItemRemoveEvent;
 use Drupal\commerce_cart\Event\CartOrderItemUpdateEvent;
-use Drupal\commerce_fedex\Event\CommerceFedExEvents;
 use Drupal\commerce_order\Entity\OrderInterface;
 use Drupal\commerce_order\Event\OrderEvents;
 use Drupal\commerce_order\Event\OrderItemEvent;
@@ -14,17 +13,29 @@
 use Drupal\commerce_shipping\Event\BeforePackEvent;
 use Drupal\commerce_shipping\Event\CommerceShippingEvents;
 use Drupal\Core\StringTranslation\StringTranslationTrait;
-use Drupal\hook_event_dispatcher\Event\Form\FormAlterEvent;
-use Drupal\hook_event_dispatcher\HookEventDispatcherEvents;
+use Drupal\core_event_dispatcher\Event\Form\FormAlterEvent;
+use Drupal\hook_event_dispatcher\HookEventDispatcherInterface;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 use Drupal\commerce_cart\Event\CartEvents;
 use Drupal\commerce_cart\Event\OrderItemComparisonFieldsEvent;
 
+/**
+ * Class CommerceQuoteCartSubscriber.
+ *
+ * @package Drupal\commerce_quote_cart\EventSubscriber
+ */
 class CommerceQuoteCartSubscriber implements EventSubscriberInterface {
   use StringTranslationTrait;
 
-  private $quoteField = 'field_quote';
-  private $purchaseField = 'field_purchase';
+  /**
+   * @var string
+   */
+  private $quoteField = 'quote';
+
+  /**
+   * @var string
+   */
+  private $purchaseField = 'purchase';
 
   /**
    * {@inheritdoc}
@@ -36,19 +47,19 @@ public static function getSubscribedEvents() {
     $events[OrderEvents::ORDER_ITEM_PRESAVE][] = ['onOrderItemPresave'];
     $events[OrderEvents::ORDER_ITEM_CREATE][] = ['onOrderItemCreate'];
     $events[CommerceShippingEvents::BEFORE_PACK][] = ['onBeforePack'];
-    $events[CommerceFedExEvents::BEFORE_PACK][] = ['onBeforePackFedEx'];
     $events[CartEvents::CART_ENTITY_ADD][] = ['onCartEntityAdd'];
     $events[CartEvents::CART_ORDER_ITEM_UPDATE][] = ['onCartOrderItemUpdate'];
     $events[CartEvents::CART_ORDER_ITEM_REMOVE][] = ['onCartOrderItemRemove'];
-    $events[HookEventDispatcherEvents::FORM_ALTER][] = ['alterCheckoutForm', -10];
-    $events[HookEventDispatcherEvents::FORM_ALTER][] = ['alterCartForm'];
-    $events[HookEventDispatcherEvents::FORM_ALTER][] = ['alterAddToCartForm'];
+    $events[HookEventDispatcherInterface::FORM_ALTER][] = ['alterCheckoutForm', -10];
+    $events[HookEventDispatcherInterface::FORM_ALTER][] = ['alterCartForm'];
+    $events[HookEventDispatcherInterface::FORM_ALTER][] = ['alterAddToCartForm'];
 
     return $events;
   }
 
   /**
-   * @param FormAlterEvent $event
+   * @param \Drupal\core_event_dispatcher\Event\Form\FormAlterEvent $event
+   *   The form alter event.
    * @throws \Drupal\Component\Plugin\Exception\InvalidPluginDefinitionException
    */
   public function alterAddToCartForm(FormAlterEvent $event) {
@@ -64,8 +75,8 @@ public function alterAddToCartForm(FormAlterEvent $event) {
       return;
     }
 
-    $availableForQuote = $variation->get('field_available_for_quote')->value || QuoteCartHelper::hasQuoteCart();
-    $availableForPurchase = $variation->get('field_available_for_purchase')->value;
+    $availableForQuote = $variation->get('available_for_quote')->value || QuoteCartHelper::hasQuoteCart();
+    $availableForPurchase = $variation->get('available_for_purchase')->value;
 
     $form['actions']['submit']['#access'] = (bool) $availableForPurchase;
 
@@ -87,9 +98,13 @@ public function alterAddToCartForm(FormAlterEvent $event) {
 
     $form['#after_build'][] = 'commerce_quote_cart_set_triggering_element';
 
-    $event->setForm($form);
+    // $event->setForm($form);
   }
 
+  /**
+   * @param \Drupal\core_event_dispatcher\Event\Form\FormAlterEvent $event
+   *   The form alter event.
+   */
   public function alterCartForm(FormAlterEvent $event) {
     $form_id = $event->getFormId();
 
@@ -122,11 +137,12 @@ public function alterCartForm(FormAlterEvent $event) {
       }
     }
 
-    $event->setForm($form);
+    // $event->setForm($form);
   }
 
   /**
-   * @param \Drupal\hook_event_dispatcher\Event\Form\FormAlterEvent $event
+   * @param \Drupal\core_event_dispatcher\Event\Form\FormAlterEvent $event
+   *   The form alter event.
    */
   public function alterCheckoutForm(FormAlterEvent $event) {
     $form_id = $event->getFormId();
@@ -135,7 +151,7 @@ public function alterCheckoutForm(FormAlterEvent $event) {
       return;
     }
 
-    $form = $event->getForm();
+    $form = &$event->getForm();
     $is_quote = !QuoteCartHelper::isPurchaseCart();
     $label = $is_quote ? 'Quote' : 'Order';
     $shipping_label = $is_quote ? 'Contact' : 'Shipping';
@@ -145,10 +161,10 @@ public function alterCheckoutForm(FormAlterEvent $event) {
     }
 
     if (isset($form['shipping_information'])) {
-      $form['shipping_information']['#title'] = t($shipping_label . ' Information');
+      $form['shipping_information']['#title'] = t('@shipping_label Information', ['@shipping_label' => $shipping_label]);
       $form['#attached']['library'][] = 'commerce_quote_cart/shipping-information';
 
-      // Hide shipping information for quote orders
+      // Hide shipping information for quote orders.
       if (isset($form['shipping_information']['shipments']) && $is_quote) {
         $form['shipping_information']['shipments']['#attributes']['class'][] = 'js-hide';
       }
@@ -163,7 +179,7 @@ public function alterCheckoutForm(FormAlterEvent $event) {
       $nextValue = $form['actions']['next']['#value'];
 
       if (strtolower($nextValue->getUntranslatedString()) == 'pay and complete purchase') {
-        $form['actions']['next']['#value'] = t('Complete ' . strtolower($label));
+        $form['actions']['next']['#value'] = t('Complete @label', ['@label' => strtolower($label)]);
       }
     }
 
@@ -172,32 +188,47 @@ public function alterCheckoutForm(FormAlterEvent $event) {
         '#type' => 'container',
         '#weight' => -1,
         'title' => [
-          '#markup' => t("$label summary"),
-        ]
+          '#markup' => t("@label summary", ['@label' => $label]),
+        ],
       ];
     }
 
-    $event->setForm($form);
   }
 
+  /**
+   * @param \Drupal\commerce_cart\Event\CartEntityAddEvent $event
+   *   The cart entity add event.
+   */
   public function onCartEntityAdd(CartEntityAddEvent $event) {
     $cart = $event->getCart();
     $this->setOrderType($cart);
     $this->cleanOrderInfo($cart);
   }
 
+  /**
+   * @param \Drupal\commerce_cart\Event\CartOrderItemUpdateEvent $event
+   *   The cart order item update event.
+   */
   public function onCartOrderItemUpdate(CartOrderItemUpdateEvent $event) {
     $cart = $event->getCart();
     $this->setOrderType($cart);
     $this->cleanOrderInfo($event->getCart());
   }
 
+  /**
+   * @param \Drupal\commerce_cart\Event\CartOrderItemRemoveEvent $event
+   *   The cart order item remove event.
+   */
   public function onCartOrderItemRemove(CartOrderItemRemoveEvent $event) {
     $cart = $event->getCart();
     $this->setOrderType($cart);
     $this->cleanOrderInfo($event->getCart());
   }
 
+  /**
+   * @param \Drupal\commerce_order\Entity\OrderInterface $order
+   *   The order interface.
+   */
   public function setOrderType(OrderInterface $order) {
     if ($order->hasField($this->quoteField)) {
       $order->get($this->quoteField)->value = QuoteCartHelper::isQuoteCart($order);
@@ -208,6 +239,10 @@ public function setOrderType(OrderInterface $order) {
     }
   }
 
+  /**
+   * @param \Drupal\commerce_order\Entity\OrderInterface $cart
+   *   The order interface.
+   */
   public function cleanOrderInfo(OrderInterface $cart) {
     // Don't do this if it's an order.
     if (QuoteCartHelper::isPurchaseCart($cart) || is_null($cart->getTotalPrice()) || $cart->getTotalPrice()->isZero()) {
@@ -217,19 +252,29 @@ public function cleanOrderInfo(OrderInterface $cart) {
     $cart->clearAdjustments();
   }
 
+  /**
+   * @param \Drupal\commerce_shipping\Event\BeforePackEvent $event
+   *  The before pack event.
+   */
   public function onBeforePack(BeforePackEvent $event) {
     $event->setOrderItems($this->filterQuoteItems($event->getOrder(), $event->getOrderItems()));
   }
 
-  public function onBeforePackFedEx(\Drupal\commerce_fedex\Event\BeforePackEvent $event) {
-    $event->setOrderItems($this->filterQuoteItems($event->getOrder(), $event->getOrderItems()));
-  }
-
+  /**
+   * @param \Drupal\commerce_order\Entity\OrderInterface $order
+   *   The order.
+   * @param array $items
+   *   Array of quote order items.
+   *
+   * @return array
+   * $items
+   */
   protected function filterQuoteItems(OrderInterface $order, array $items) {
-    // Only remove quote items from purchases, as we need as least one shippable item.
+    // Only remove quote items from purchases, as we need at least one shippable
+    // item.
     if (QuoteCartHelper::isPurchaseCart($order)) {
       foreach ($items as $id => $orderItem) {
-        if ($orderItem->hasField('field_quote') && $orderItem->get('field_quote')->value) {
+        if ($orderItem->hasField('quote') && $orderItem->get('quote')->value) {
           unset($items[$id]);
         }
       }
@@ -238,6 +283,10 @@ protected function filterQuoteItems(OrderInterface $order, array $items) {
     return $items;
   }
 
+  /**
+   * @param \Drupal\commerce_cart\Event\OrderItemComparisonFieldsEvent $event
+   *  The order item comparison fields event.
+   */
   public function onOrderItemComparisonFields(OrderItemComparisonFieldsEvent $event) {
     $fields = $event->getComparisonFields();
 
@@ -246,6 +295,10 @@ public function onOrderItemComparisonFields(OrderItemComparisonFieldsEvent $even
     $event->setComparisonFields($fields);
   }
 
+  /**
+   * @param \Drupal\commerce_order\Event\OrderItemEvent $event
+   *   The order item event.
+   */
   public function onOrderItemPresave(OrderItemEvent $event) {
     $orderItem = $event->getOrderItem();
 
@@ -254,7 +307,12 @@ public function onOrderItemPresave(OrderItemEvent $event) {
     }
   }
 
+  /**
+   * @param \Drupal\commerce_order\Event\OrderItemEvent $event
+   *   The order item event.
+   */
   public function onOrderItemCreate(OrderItemEvent $event) {
     $event->getOrderItem()->set($this->quoteField, ['value' => "0"]);
   }
+
 }
diff --git a/src/Plugin/Commerce/CheckoutFlow/MultistepQuote.php b/src/Plugin/Commerce/CheckoutFlow/MultistepQuote.php
index ccd35c9..fccef41 100644
--- a/src/Plugin/Commerce/CheckoutFlow/MultistepQuote.php
+++ b/src/Plugin/Commerce/CheckoutFlow/MultistepQuote.php
@@ -1,7 +1,12 @@
 <?php
 
 namespace Drupal\commerce_quote_cart\Plugin\Commerce\CheckoutFlow;
-use Drupal\commerce_customizations\Plugin\Commerce\CheckoutFlow\MultistepOrder;
+
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Url;
+use Drupal\commerce\Response\NeedsRedirectException;
+use Drupal\commerce_checkout\Plugin\Commerce\CheckoutFlow\MultistepDefault;
+use Drupal\commerce_quote_cart\QuoteCartHelper;
 
 /**
  * Provides the quote multistep checkout flow.
@@ -11,7 +16,7 @@
  *   label = "Multistep - Quote",
  * )
  */
-class MultistepQuote extends MultistepOrder {
+class MultistepQuote extends MultistepDefault {
 
   /**
    * {@inheritdoc}
@@ -23,5 +28,58 @@ public function getSteps() {
 
     return $steps;
   }
+  /**
+   * {@inheritdoc}
+   */
+  public function redirectToStep($step_id) {
+    $this->order->set('checkout_step', $step_id);
+    if ($step_id == 'complete') {
+      $transition = $this->order->getState()->getWorkflow()->getTransition('place');
+      $this->order->getState()->applyTransition($transition);
+    }
+    $this->order->save();
+    $url = Url::fromRoute('commerce_checkout.form', [
+      'commerce_order' => $this->order->id(),
+      'step' => $step_id,
+    ], $this->getUrlOptions($step_id));
+    throw new NeedsRedirectException($url->toString());
+  }
+
+  /**
+   * @param array $form
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
+   */
+  public function submitForm(array &$form, FormStateInterface $form_state) {
+    parent::submitForm($form, $form_state);
 
+    if ($next_step_id = $this->getNextStepId($form['#step_id'])) {
+      if ($next_step_id == 'complete') {
+        $form_state->setRedirect('commerce_checkout.form', [
+          'commerce_order' => $this->order->id(),
+          'step' => $next_step_id,
+        ], $this->getUrlOptions($next_step_id));
+      }
+    }
+  }
+
+  /**
+   * @param $step_id
+   *
+   * @return array|\string[][]
+   */
+  protected function getUrlOptions($step_id) {
+    $options = [];
+    if ($step_id == 'complete') {
+      $type = 'quote';
+      if (QuoteCartHelper::isMixedCart($this->order)) {
+        $type = 'mixed';
+      } elseif (QuoteCartHelper::isPurchaseCart($this->order)) {
+        $type = 'order';
+      }
+
+      $options = ['query' => ['type' => $type]];
+    }
+
+    return $options;
+  }
 }
diff --git a/src/QuoteCartHelper.php b/src/QuoteCartHelper.php
index fd2ce47..0ebd617 100644
--- a/src/QuoteCartHelper.php
+++ b/src/QuoteCartHelper.php
@@ -71,7 +71,7 @@ public static function isPurchaseCart(OrderInterface $cartOrder = NULL) {
 
     $isPurchaseCart = FALSE;
 
-    $field = 'field_quote';
+    $field = 'quote';
 
     /** @var OrderItemInterface $item */
     foreach ($cartOrder->getItems() as $item) {
@@ -99,7 +99,7 @@ public static function isQuoteCart(OrderInterface $cartOrder = NULL) {
 
     $isQuoteCart = FALSE;
 
-    $field = 'field_quote';
+    $field = 'quote';
 
     foreach ($cartOrder->getItems() as $item) {
       if ($item->hasField($field) && $item->get($field)->value) {
@@ -116,7 +116,7 @@ public static function isQuoteCart(OrderInterface $cartOrder = NULL) {
    * @throws EntityStorageException
    */
   public static function convertToQuote(OrderInterface $cartOrder) {
-    $field = 'field_quote';
+    $field = 'quote';
     $save = FALSE;
 
     foreach ($cartOrder->getItems() as $item) {
@@ -137,7 +137,7 @@ public static function convertToQuote(OrderInterface $cartOrder) {
   }
 
   public static function isQuoteItem(OrderItemInterface $orderItem) {
-    $fieldName = 'field_quote';
+    $fieldName = 'quote';
 
     return ($orderItem->hasField($fieldName) && $orderItem->get($fieldName)->value);
   }
@@ -147,7 +147,7 @@ public static function isQuoteItem(OrderItemInterface $orderItem) {
    * @throws EntityStorageException
    */
   public static function convertItemToQuote(OrderItemInterface $item) {
-    $field = 'field_quote';
+    $field = 'quote';
 
     if (!$item->hasField($field)) {
       return;