diff --git a/composer.json b/composer.json
index 9056b00..b400d1d 100644
--- a/composer.json
+++ b/composer.json
@@ -7,7 +7,7 @@
   "prefer-stable": true,
   "minimum-stability": "dev",
   "require": {
-    "automattic/jetpack-autoloader": "^2.0.0"
+    "automattic/jetpack-autoloader": "^2.2.0"
   },
   "require-dev": {
     "phpunit/phpunit": "6.5.14",
diff --git a/src/Controllers/Version2/class-wc-rest-coupons-v2-controller.php b/src/Controllers/Version2/class-wc-rest-coupons-v2-controller.php
index e8ab107..7dbcaa1 100644
--- a/src/Controllers/Version2/class-wc-rest-coupons-v2-controller.php
+++ b/src/Controllers/Version2/class-wc-rest-coupons-v2-controller.php
@@ -511,7 +511,7 @@ public function get_item_schema() {
 							),
 							'value' => array(
 								'description' => __( 'Meta value.', 'woocommerce-rest-api' ),
-								'type'        => array( 'string', 'null' ),
+								'type'        => 'mixed',
 								'context'     => array( 'view', 'edit' ),
 							),
 						),
diff --git a/src/Controllers/Version2/class-wc-rest-customers-v2-controller.php b/src/Controllers/Version2/class-wc-rest-customers-v2-controller.php
index 22fb257..29d4e07 100644
--- a/src/Controllers/Version2/class-wc-rest-customers-v2-controller.php
+++ b/src/Controllers/Version2/class-wc-rest-customers-v2-controller.php
@@ -350,7 +350,7 @@ public function get_item_schema() {
 							),
 							'value' => array(
 								'description' => __( 'Meta value.', 'woocommerce-rest-api' ),
-								'type'        => array( 'string', 'null' ),
+								'type'        => 'mixed',
 								'context'     => array( 'view', 'edit' ),
 							),
 						),
diff --git a/src/Controllers/Version2/class-wc-rest-order-refunds-v2-controller.php b/src/Controllers/Version2/class-wc-rest-order-refunds-v2-controller.php
index c0b30dc..dff06e2 100644
--- a/src/Controllers/Version2/class-wc-rest-order-refunds-v2-controller.php
+++ b/src/Controllers/Version2/class-wc-rest-order-refunds-v2-controller.php
@@ -410,7 +410,7 @@ public function get_item_schema() {
 							),
 							'value' => array(
 								'description' => __( 'Meta value.', 'woocommerce-rest-api' ),
-								'type'        => array( 'string', 'null' ),
+								'type'        => 'mixed',
 								'context'     => array( 'view', 'edit' ),
 							),
 						),
@@ -432,13 +432,13 @@ public function get_item_schema() {
 							),
 							'name'         => array(
 								'description' => __( 'Product name.', 'woocommerce-rest-api' ),
-								'type'        => array( 'string', 'null' ),
+								'type'        => 'mixed',
 								'context'     => array( 'view', 'edit' ),
 								'readonly'    => true,
 							),
 							'product_id'   => array(
 								'description' => __( 'Product ID.', 'woocommerce-rest-api' ),
-								'type'        => array( 'integer', 'null' ),
+								'type'        => 'mixed',
 								'context'     => array( 'view', 'edit' ),
 								'readonly'    => true,
 							),
@@ -535,7 +535,7 @@ public function get_item_schema() {
 										),
 										'value' => array(
 											'description' => __( 'Meta value.', 'woocommerce-rest-api' ),
-											'type'        => array( 'string', 'null' ),
+											'type'        => 'mixed',
 											'context'     => array( 'view', 'edit' ),
 											'readonly'    => true,
 										),
diff --git a/src/Controllers/Version2/class-wc-rest-orders-v2-controller.php b/src/Controllers/Version2/class-wc-rest-orders-v2-controller.php
index 2744e42..a9422ae 100644
--- a/src/Controllers/Version2/class-wc-rest-orders-v2-controller.php
+++ b/src/Controllers/Version2/class-wc-rest-orders-v2-controller.php
@@ -1170,7 +1170,7 @@ public function get_item_schema() {
 							),
 							'value' => array(
 								'description' => __( 'Meta value.', 'woocommerce-rest-api' ),
-								'type'        => array( 'string', 'null' ),
+								'type'        => 'mixed',
 								'context'     => array( 'view', 'edit' ),
 							),
 						),
@@ -1191,12 +1191,12 @@ public function get_item_schema() {
 							),
 							'name'         => array(
 								'description' => __( 'Product name.', 'woocommerce-rest-api' ),
-								'type'        => array( 'string', 'null' ),
+								'type'        => 'mixed',
 								'context'     => array( 'view', 'edit' ),
 							),
 							'product_id'   => array(
 								'description' => __( 'Product ID.', 'woocommerce-rest-api' ),
-								'type'        => array( 'integer' ),
+								'type'        => 'mixed',
 								'context'     => array( 'view', 'edit' ),
 							),
 							'variation_id' => array(
@@ -1282,7 +1282,7 @@ public function get_item_schema() {
 										),
 										'value' => array(
 											'description' => __( 'Meta value.', 'woocommerce-rest-api' ),
-											'type'        => array( 'string', 'null' ),
+											'type'        => 'mixed',
 											'context'     => array( 'view', 'edit' ),
 										),
 									),
@@ -1373,7 +1373,7 @@ public function get_item_schema() {
 										),
 										'value' => array(
 											'description' => __( 'Meta value.', 'woocommerce-rest-api' ),
-											'type'        => array( 'string', 'null' ),
+											'type'        => 'mixed',
 											'context'     => array( 'view', 'edit' ),
 										),
 									),
@@ -1397,12 +1397,12 @@ public function get_item_schema() {
 							),
 							'method_title' => array(
 								'description' => __( 'Shipping method name.', 'woocommerce-rest-api' ),
-								'type'        => array( 'string', 'null' ),
+								'type'        => 'mixed',
 								'context'     => array( 'view', 'edit' ),
 							),
 							'method_id'    => array(
 								'description' => __( 'Shipping method ID.', 'woocommerce-rest-api' ),
-								'type'        => array( 'string', 'null' ),
+								'type'        => 'mixed',
 								'context'     => array( 'view', 'edit' ),
 							),
 							'instance_id'  => array(
@@ -1464,7 +1464,7 @@ public function get_item_schema() {
 										),
 										'value' => array(
 											'description' => __( 'Meta value.', 'woocommerce-rest-api' ),
-											'type'        => array( 'string', 'null' ),
+											'type'        => 'mixed',
 											'context'     => array( 'view', 'edit' ),
 										),
 									),
@@ -1488,7 +1488,7 @@ public function get_item_schema() {
 							),
 							'name'       => array(
 								'description' => __( 'Fee name.', 'woocommerce-rest-api' ),
-								'type'        => array( 'string', 'null' ),
+								'type'        => 'mixed',
 								'context'     => array( 'view', 'edit' ),
 							),
 							'tax_class'  => array(
@@ -1562,7 +1562,7 @@ public function get_item_schema() {
 										),
 										'value' => array(
 											'description' => __( 'Meta value.', 'woocommerce-rest-api' ),
-											'type'        => array( 'string', 'null' ),
+											'type'        => 'mixed',
 											'context'     => array( 'view', 'edit' ),
 										),
 									),
@@ -1586,7 +1586,7 @@ public function get_item_schema() {
 							),
 							'code'         => array(
 								'description' => __( 'Coupon code.', 'woocommerce-rest-api' ),
-								'type'        => array( 'string', 'null' ),
+								'type'        => 'mixed',
 								'context'     => array( 'view', 'edit' ),
 							),
 							'discount'     => array(
@@ -1620,7 +1620,7 @@ public function get_item_schema() {
 										),
 										'value' => array(
 											'description' => __( 'Meta value.', 'woocommerce-rest-api' ),
-											'type'        => array( 'string', 'null' ),
+											'type'        => 'mixed',
 											'context'     => array( 'view', 'edit' ),
 										),
 									),
diff --git a/src/Controllers/Version2/class-wc-rest-product-variations-v2-controller.php b/src/Controllers/Version2/class-wc-rest-product-variations-v2-controller.php
index 4941870..392098a 100644
--- a/src/Controllers/Version2/class-wc-rest-product-variations-v2-controller.php
+++ b/src/Controllers/Version2/class-wc-rest-product-variations-v2-controller.php
@@ -799,7 +799,7 @@ public function get_item_schema() {
 				),
 				'manage_stock'          => array(
 					'description' => __( 'Stock management at variation level.', 'woocommerce-rest-api' ),
-					'type'        => array( 'boolean', 'null' ),
+					'type'        => 'mixed',
 					'default'     => false,
 					'context'     => array( 'view', 'edit' ),
 				),
@@ -982,7 +982,7 @@ public function get_item_schema() {
 							),
 							'value' => array(
 								'description' => __( 'Meta value.', 'woocommerce-rest-api' ),
-								'type'        => array( 'string', 'null' ),
+								'type'        => 'mixed',
 								'context'     => array( 'view', 'edit' ),
 							),
 						),
diff --git a/src/Controllers/Version2/class-wc-rest-products-v2-controller.php b/src/Controllers/Version2/class-wc-rest-products-v2-controller.php
index 8155463..f38ecb7 100644
--- a/src/Controllers/Version2/class-wc-rest-products-v2-controller.php
+++ b/src/Controllers/Version2/class-wc-rest-products-v2-controller.php
@@ -2084,7 +2084,7 @@ public function get_item_schema() {
 							),
 							'value' => array(
 								'description' => __( 'Meta value.', 'woocommerce-rest-api' ),
-								'type'        => array( 'string', 'null' ),
+								'type'        => 'mixed',
 								'context'     => array( 'view', 'edit' ),
 							),
 						),
diff --git a/src/Controllers/Version2/class-wc-rest-setting-options-v2-controller.php b/src/Controllers/Version2/class-wc-rest-setting-options-v2-controller.php
index e23aa3a..7c8a72a 100644
--- a/src/Controllers/Version2/class-wc-rest-setting-options-v2-controller.php
+++ b/src/Controllers/Version2/class-wc-rest-setting-options-v2-controller.php
@@ -530,18 +530,12 @@ public function get_item_schema() {
 				),
 				'value'       => array(
 					'description' => __( 'Setting value.', 'woocommerce-rest-api' ),
-					'type'        => array( 'string', 'array', 'null' ),
-					'items'       => array(
-						'type' => array( 'string', 'null' ),
-					),
+					'type'        => 'mixed',
 					'context'     => array( 'view', 'edit' ),
 				),
 				'default'     => array(
 					'description' => __( 'Default value for the setting.', 'woocommerce-rest-api' ),
-					'type'        => array( 'string', 'array', 'null' ),
-					'items'       => array(
-						'type' => array( 'string', 'null' ),
-					),
+					'type'        => 'mixed',
 					'context'     => array( 'view', 'edit' ),
 					'readonly'    => true,
 				),
diff --git a/src/Controllers/Version3/class-wc-rest-controller.php b/src/Controllers/Version3/class-wc-rest-controller.php
index d851be5..7f16389 100644
--- a/src/Controllers/Version3/class-wc-rest-controller.php
+++ b/src/Controllers/Version3/class-wc-rest-controller.php
@@ -93,16 +93,57 @@ public function get_endpoint_args_for_item_schema( $method = WP_REST_Server::CRE
 			return $endpoint_args;
 		}
 
+		$endpoint_args = $this->adjust_wp_5_5_datatype_compatibility( $endpoint_args );
+
+		return $endpoint_args;
+	}
+
+	/**
+	 * Change datatypes `date-time` to string, and `mixed` to composite of all built in types. This is required for maintaining forward compatibility with WP 5.5 since custom post types are not supported anymore.
+	 *
+	 * See @link https://core.trac.wordpress.org/changeset/48306
+	 *
+	 * We still use the 'mixed' type, since if we convert to composite type everywhere, it won't work in 5.4 anymore because they require to define the full schema.
+	 *
+	 * @param array $endpoint_args Schema with datatypes to convert.
+
+	 * @return mixed Schema with converted datatype.
+	 */
+	protected function adjust_wp_5_5_datatype_compatibility( $endpoint_args ) {
+		if ( version_compare( get_bloginfo( 'version' ), '5.5', '<' ) ) {
+			return $endpoint_args;
+		}
+
 		foreach ( $endpoint_args as $field_id => $params ) {
+
+			if ( ! isset( $params['type'] ) ) {
+				continue;
+			}
+
 			/**
-			 * Custom types are not supported as of WP 5.5, this translates type => 'date-time' to type => 'string' with format date-time.
+			 * Custom types are not supported as of WP 5.5, this translates type => 'date-time' to type => 'string'.
 			 */
 			if ( 'date-time' === $params['type'] ) {
-				$endpoint_args[ $field_id ]['type']   = 'string';
-				$endpoint_args[ $field_id ]['format'] = 'date-time';
+				$params['type'] = array( 'null', 'string' );
+			}
+
+			/**
+			 * WARNING: Order of fields here is important, types of fields are ordered from most specific to least specific as perceived by core's built-in type validation methods.
+			 */
+			if ( 'mixed' === $params['type'] ) {
+				$params['type'] = array( 'null', 'object', 'string', 'number', 'boolean', 'integer', 'array' );
+			}
+
+			if ( isset( $params['properties'] ) ) {
+				$params['properties'] = $this->adjust_wp_5_5_datatype_compatibility( $params['properties'] );
 			}
-		}
 
+			if ( isset( $params['items'] ) && isset( $params['items']['properties'] ) ) {
+				$params['items']['properties'] = $this->adjust_wp_5_5_datatype_compatibility( $params['items']['properties'] );
+			}
+
+			$endpoint_args[ $field_id ] = $params;
+		}
 		return $endpoint_args;
 	}
 
diff --git a/src/Controllers/Version3/class-wc-rest-crud-controller.php b/src/Controllers/Version3/class-wc-rest-crud-controller.php
index 7aaa3af..c12186e 100644
--- a/src/Controllers/Version3/class-wc-rest-crud-controller.php
+++ b/src/Controllers/Version3/class-wc-rest-crud-controller.php
@@ -91,8 +91,6 @@ public function delete_item_permissions_check( $request ) {
 		return true;
 	}
 
-
-
 	/**
 	 * Get object permalink.
 	 *
diff --git a/src/Controllers/Version3/class-wc-rest-customers-controller.php b/src/Controllers/Version3/class-wc-rest-customers-controller.php
index 072fb08..65ce592 100644
--- a/src/Controllers/Version3/class-wc-rest-customers-controller.php
+++ b/src/Controllers/Version3/class-wc-rest-customers-controller.php
@@ -293,7 +293,7 @@ public function get_item_schema() {
 							),
 							'value' => array(
 								'description' => __( 'Meta value.', 'woocommerce-rest-api' ),
-								'type'        => array( 'string', 'null' ),
+								'type'        => 'mixed',
 								'context'     => array( 'view', 'edit' ),
 							),
 						),
diff --git a/src/Controllers/Version3/class-wc-rest-product-variations-controller.php b/src/Controllers/Version3/class-wc-rest-product-variations-controller.php
index 6c71016..0477e81 100644
--- a/src/Controllers/Version3/class-wc-rest-product-variations-controller.php
+++ b/src/Controllers/Version3/class-wc-rest-product-variations-controller.php
@@ -736,7 +736,7 @@ public function get_item_schema() {
 							),
 							'value' => array(
 								'description' => __( 'Meta value.', 'woocommerce-rest-api' ),
-								'type'        => array( 'string', 'null' ),
+								'type'        => 'mixed',
 								'context'     => array( 'view', 'edit' ),
 							),
 						),
diff --git a/src/Controllers/Version3/class-wc-rest-products-controller.php b/src/Controllers/Version3/class-wc-rest-products-controller.php
index 6f3d3a0..a6401bf 100644
--- a/src/Controllers/Version3/class-wc-rest-products-controller.php
+++ b/src/Controllers/Version3/class-wc-rest-products-controller.php
@@ -1288,7 +1288,7 @@ public function get_item_schema() {
 							),
 							'value' => array(
 								'description' => __( 'Meta value.', 'woocommerce-rest-api' ),
-								'type'        => array( 'string', 'null' ),
+								'type'        => 'mixed',
 								'context'     => array( 'view', 'edit' ),
 							),
 						),
diff --git a/src/Controllers/Version3/class-wc-rest-setting-options-controller.php b/src/Controllers/Version3/class-wc-rest-setting-options-controller.php
index 59d3828..b725569 100644
--- a/src/Controllers/Version3/class-wc-rest-setting-options-controller.php
+++ b/src/Controllers/Version3/class-wc-rest-setting-options-controller.php
@@ -199,18 +199,12 @@ public function get_item_schema() {
 				),
 				'value'       => array(
 					'description' => __( 'Setting value.', 'woocommerce-rest-api' ),
-					'type'        => array( 'string', 'array', 'null' ),
-					'items'       => array(
-						'type' => array( 'string', 'null' ),
-					),
+					'type'        => 'mixed',
 					'context'     => array( 'view', 'edit' ),
 				),
 				'default'     => array(
 					'description' => __( 'Default value for the setting.', 'woocommerce-rest-api' ),
-					'type'        => array( 'string', 'array', 'null' ),
-					'items'       => array(
-						'type' => array( 'string', 'null' ),
-					),
+					'type'        => 'mixed',
 					'context'     => array( 'view', 'edit' ),
 					'readonly'    => true,
 				),
diff --git a/unit-tests/Bootstrap.php b/unit-tests/Bootstrap.php
index b10c7f8..a21c4cc 100755
--- a/unit-tests/Bootstrap.php
+++ b/unit-tests/Bootstrap.php
@@ -128,6 +128,9 @@ protected function load_framework() {
 		require_once $this->tests_dir . '/Helpers/SettingsHelper.php';
 		require_once $this->tests_dir . '/Helpers/QueueHelper.php';
 		require_once $this->tests_dir . '/AbstractRestApiTest.php';
+
+		// Traits.
+		require_once $this->tests_dir . '/traits/trait-wc-rest-api-complex-meta.php';
 	}
 }
 
diff --git a/unit-tests/Tests/Version2/product-variations.php b/unit-tests/Tests/Version2/product-variations.php
index 22a53d4..560e886 100644
--- a/unit-tests/Tests/Version2/product-variations.php
+++ b/unit-tests/Tests/Version2/product-variations.php
@@ -7,6 +7,7 @@
  */
 
 class Product_Variations_API_V2 extends WC_REST_Unit_Test_Case {
+	use WC_REST_API_Complex_Meta;
 
 	/**
 	 * Setup our test server, endpoints, and user info.
@@ -299,6 +300,19 @@ public function test_create_variation() {
 		$this->assertEquals( 3, count( $variations ) );
 	}
 
+	/**
+	 * Test updating complex meta object.
+	 */
+	public function test_update_complex_meta_27282() {
+		wp_set_current_user( $this->user );
+		$product = \Automattic\WooCommerce\RestApi\UnitTests\Helpers\ProductHelper::create_variation_product();
+		$product->save();
+		$variations = $product->get_available_variations( 'objects' );
+		$first_variation_id = $variations[0]->get_id();
+		$url = '/wc/v2/products/' . $product->get_id() . '/variations/' . $first_variation_id;
+		$this->assert_update_complex_meta( $url );
+	}
+
 	/**
 	 * Test creating a single variation without permission.
 	 *
diff --git a/unit-tests/Tests/Version3/orders.php b/unit-tests/Tests/Version3/orders.php
index 6ebb747..ea5768c 100644
--- a/unit-tests/Tests/Version3/orders.php
+++ b/unit-tests/Tests/Version3/orders.php
@@ -10,6 +10,7 @@
  * Class WC_Tests_API_Orders
  */
 class WC_Tests_API_Orders extends WC_REST_Unit_Test_Case {
+	use WC_REST_API_Complex_Meta;
 
 	/**
 	 * Array of order to track
@@ -76,12 +77,22 @@ public function test_get_items_ordered_by_modified() {
 		$order2->save();
 
 		$request = new WP_REST_Request( 'GET', '/wc/v3/orders' );
-		$request->set_query_params( array( 'orderby' => 'modified', 'order' => 'asc' ) );
+		$request->set_query_params(
+			array(
+				'orderby' => 'modified',
+				'order' => 'asc',
+			)
+		);
 		$response = $this->server->dispatch( $request );
 		$orders   = $response->get_data();
 		$this->assertEquals( $order1->get_id(), $orders[0]['id'] );
 
-		$request->set_query_params( array( 'orderby' => 'modified', 'order' => 'desc' ) );
+		$request->set_query_params(
+			array(
+				'orderby' => 'modified',
+				'order' => 'desc',
+			)
+		);
 		$response = $this->server->dispatch( $request );
 		$orders   = $response->get_data();
 		$this->assertEquals( $order2->get_id(), $orders[0]['id'] );
@@ -208,6 +219,20 @@ public function test_create_order() {
 						'method_title' => 'Flat rate',
 						'total'        => '10.00',
 						'instance_id'  => '1',
+						'meta_data'    => array(
+							array(
+								'key'   => 'string',
+								'value' => 'string_val',
+							),
+							array(
+								'key'   => 'integer',
+								'value' => 1,
+							),
+							array(
+								'key'   => 'array',
+								'value' => array( 1, 2 ),
+							),
+						),
 					),
 				),
 			)
diff --git a/unit-tests/Tests/Version3/products.php b/unit-tests/Tests/Version3/products.php
index 2235189..fa00aa6 100644
--- a/unit-tests/Tests/Version3/products.php
+++ b/unit-tests/Tests/Version3/products.php
@@ -10,6 +10,7 @@
   * WC_Tests_API_Product class.
   */
 class WC_Tests_API_Product extends WC_REST_Unit_Test_Case {
+	use WC_REST_API_Complex_Meta;
 
 	/**
 	 * Setup our test server, endpoints, and user info.
@@ -218,7 +219,7 @@ public function test_update_product() {
 		$product      = \Automattic\WooCommerce\RestApi\UnitTests\Helpers\ProductHelper::create_simple_product();
 		$response     = $this->server->dispatch( new WP_REST_Request( 'GET', '/wc/v3/products/' . $product->get_id() ) );
 		$data         = $response->get_data();
-		$date_created = date( 'Y-m-d\TH:i:s', current_time( 'timestamp' ) );
+		$date_created = gmdate( 'Y-m-d\TH:i:s', current_time( 'timestamp' ) );
 
 		$this->assertEquals( 'DUMMY SKU', $data['sku'] );
 		$this->assertEquals( 10, $data['regular_price'] );
@@ -455,6 +456,55 @@ public function test_create_product() {
 		$this->assertEquals( 3, count( $products ) );
 	}
 
+	/**
+	 * Test to update complex metadata.
+	 */
+	public function test_update_complex_meta_27282() {
+		wp_set_current_user( $this->user );
+		$product = \Automattic\WooCommerce\RestApi\UnitTests\Helpers\ProductHelper::create_simple_product();
+		$product->save();
+		$url = '/wc/v3/products/' . $product->get_id();
+		$this->assert_update_complex_meta( $url );
+	}
+
+	/**
+	 * Test to update datetime property.
+	 */
+	public function test_update_date_time() {
+		wp_set_current_user( $this->user );
+		$product = \Automattic\WooCommerce\RestApi\UnitTests\Helpers\ProductHelper::create_simple_product();
+		$product->save();
+		$date_from_sale = '2020-01-01T01:01:01';
+
+		$request = new WP_REST_Request( 'PUT', '/wc/v3/products/' . $product->get_id() );
+
+		$request->set_body_params( array( 'date_on_sale_from' => $date_from_sale ) );
+		$response = $this->server->dispatch( $request );
+		$this->assertEquals( 200, $response->get_status() );
+		$data = $response->get_data();
+		$this->assertEquals( $date_from_sale, $data['date_on_sale_from'] );
+
+		// Empty string should delete.
+		$request->set_body_params( array( 'date_on_sale_from' => '' ) );
+		$response = $this->server->dispatch( $request );
+		$this->assertEquals( 200, $response->get_status() );
+		$data = $response->get_data();
+		$this->assertEquals( null, $data['date_on_sale_from'] );
+
+		$request->set_body_params( array( 'date_on_sale_from' => $date_from_sale ) );
+		$response = $this->server->dispatch( $request );
+		$this->assertEquals( 200, $response->get_status() );
+		$data = $response->get_data();
+		$this->assertEquals( $date_from_sale, $data['date_on_sale_from'] );
+
+		// Null does not delete.
+		$request->set_body_params( array( 'date_on_sale_from' => null ) );
+		$response = $this->server->dispatch( $request );
+		$this->assertEquals( 200, $response->get_status() );
+		$data = $response->get_data();
+		$this->assertEquals( $date_from_sale, $data['date_on_sale_from'] );
+	}
+
 	/**
 	 * Test creating a single product without permission.
 	 *
diff --git a/unit-tests/bin/install.sh b/unit-tests/bin/install.sh
index 8ab83ff..5ad1c12 100755
--- a/unit-tests/bin/install.sh
+++ b/unit-tests/bin/install.sh
@@ -174,6 +174,7 @@ install_deps() {
 
 	curl -O https://raw.githubusercontent.com/wp-cli/builds/gh-pages/phar/wp-cli.phar
 	php wp-cli.phar core config --dbname=$DB_NAME --dbuser=$DB_USER --dbpass=$DB_PASS --dbhost=$DB_HOST --dbprefix=wptests_
+	php wp-cli.phar config set JETPACK_AUTOLOAD_DEV true --raw
 	php wp-cli.phar core install --url="$WP_SITE_URL" --title="Example" --admin_user=admin --admin_password=password --admin_email=info@example.com --path=$WP_CORE_DIR --skip-email
 
 	# Install WooCommerce and WooCommerce Admin
diff --git a/unit-tests/traits/trait-wc-rest-api-complex-meta.php b/unit-tests/traits/trait-wc-rest-api-complex-meta.php
new file mode 100644
index 0000000..1b51c8b
--- /dev/null
+++ b/unit-tests/traits/trait-wc-rest-api-complex-meta.php
@@ -0,0 +1,83 @@
+<?php
+/**
+ * Trait for easier testing of objects that have `mixed` data type somewhere.
+ *
+ * @package Automattic/WooCommerce/Tests/WC_REST_API_Complex_Meta.
+ */
+
+/**
+ * Trait WC_REST_API_Complex_Meta
+ */
+trait WC_REST_API_Complex_Meta {
+
+	/**
+	 * Sample data of different built in data types.
+	 *
+	 * @var array
+	 */
+	public static $sample_meta = array(
+		array(
+			'key' => 'string_meta',
+			'value' => 'string_value',
+		),
+		array(
+			'key' => 'int_meta',
+			'value' => 1,
+		),
+		array(
+			'key' => 'bool_meta',
+			'value' => true,
+		),
+		array(
+			'key' => 'array_meta',
+			'value' => array( 1, 2, 'string' ),
+		),
+		array(
+			'key' => 'null_meta',
+			'value' => 'null',
+		),
+		array(
+			'key' => 'object_meta',
+			'value' => array(
+				'nested_key1' => 'nested_value1',
+				'nested_key2' => 0,
+				'nested_key3' => true,
+				'nested_key4' => array( 2, 3, 4 ),
+				'nested_key5' => array( 2, 3, array( 'deep' => 'nesting' ) ),
+			),
+		),
+	);
+
+	/**
+	 * Test to update `meta_data` field with a complex data type.
+	 *
+	 * @param string $url     URL to send request against.
+	 * @param array  $options Options for customizations.
+	 */
+	public function assert_update_complex_meta( $url, $options = array() ) {
+		$meta = $options['meta'] ?? self::$sample_meta;
+		$request = new WP_REST_Request( 'PUT', $url );
+		$request->set_body_params( array( 'meta_data' => $meta ) );
+
+		$response = $this->server->dispatch( $request );
+
+		$data = $response->get_data();
+
+		$this->assertEquals( 200, $response->get_status() );
+
+		$response_meta = $data['meta_data'];
+
+		foreach ( $meta as $meta_object ) {
+			$found = false;
+			foreach ( $response_meta as $response_meta_object ) {
+				if ( $response_meta_object->key === $meta_object['key'] ) {
+					$response_value = $response_meta_object->value;
+					$this->assertEquals( $meta_object['value'], $response_value );
+					$found = true;
+					break;
+				}
+			}
+			$this->assertEquals( true, $found, sprintf( 'Meta key %s was not found in response.', $meta_object['key'] ) );
+		}
+	}
+}