diff --git a/CRM/Donrec/DataStructure.php b/CRM/Donrec/DataStructure.php
index ae1731a..4719a2f 100644
--- a/CRM/Donrec/DataStructure.php
+++ b/CRM/Donrec/DataStructure.php
@@ -21,18 +21,19 @@ class CRM_Donrec_DataStructure {
     'style' => 'Inline',
     'collapse_display' => 1,
     'is_active' => 1,
-    'is_multiple' => 1,
   );
   public static $customGroups = array(
     array(
       'name' => 'zwb_donation_receipt',
       'title' => 'donation-receipt',
       'extends' => 'Contact',
+      'is_multiple' => 1,
     ),
     array(
       'name' => 'zwb_donation_receipt_item',
       'title' => 'donation-receipt-item',
       'extends' => 'Contribution',
+      'is_multiple' => 0,
     )
   );
   public static $customFieldDefaults = array(
diff --git a/CRM/Donrec/Upgrader.php b/CRM/Donrec/Upgrader.php
index 181b721..38ec8fd 100644
--- a/CRM/Donrec/Upgrader.php
+++ b/CRM/Donrec/Upgrader.php
@@ -513,4 +513,17 @@ public function upgrade_0220() {
     return TRUE;
   }
 
+  /**
+   * Upgrade to 2.2:
+   * - Update zwb_donation_receipt_item custom field group
+   * @link https://github.com/systopia/de.systopia.donrec/issues/156
+   */
+  public function upgrade_0230() {
+    civicrm_api3('CustomGroup', 'get', [
+      'name' => "zwb_donation_receipt_item",
+      'api.CustomGroup.create' => ['id' => "\$value.id", 'is_multiple' => 0],
+    ]);
+    return TRUE;
+  }
+
 }