Submission Review Guidelines:

• I have followed the WooCommerce Contributing Guidelines and the WordPress Coding Standards.
• I have checked to ensure there aren't other open Pull Requests for the same update/change.
• I have reviewed my code for security best practices.
• Following the above guidelines will result in quick merges and clear and detailed feedback when appropriate.

Changes proposed in this Pull Request:

Closes #32536

When PHP attempts to strtolower() for non-ASCII chars, the converted value is corrupted which is why the search for coupons with titles like e.g. VÅR20 failed. This PR removes the lowercase, similarly to how it was done in #25314.

How to test the changes in this Pull Request:

0️⃣ Preparation steps

• Change the collation for your DB and all the tables in it with the following steps

Once inside the database, click on the "Operations" tab in the top menu.
Change Database Collation:
Scroll down to the "Collation" section.
From the dropdown menu, select latin1_swedish_ci.
Check the boxes for "Change all tables collations" and "Change all tables columns collations".
Click Go to apply changes.

• Use the following SQL to check whether the table has the latin1_swedish_ci collation set

SELECT TABLE_NAME, TABLE_COLLATION 
FROM information_schema.TABLES 
WHERE TABLE_SCHEMA = 'wordpress'
AND TABLE_NAME = 'wp_posts';

Also define the collation and charset constants in docker/wordpress/wp-config.php

define('DB_CHARSET', 'latin1');
define('DB_COLLATE', 'latin1_swedish_ci');

1️⃣ Adding coupons

• Go to WooCommerce → Coupons → Add New
• Enter a coupon code with mixed case (e.g., SummerSale2025)
• Create the coupon with the following title: VÅR20

2️⃣ Applying coupons

On the shortcode

• Apply the VÅR20 coupon and confirm it's applied
• Remove the VÅR20 and confirm it's removed
• Apply the vÅr20 coupon and confirm case-insensitivity as the coupon should be applied too
• Apply the SummerSale2025 coupon and confirm it's applied
• Apply the SUMMERSALE2025 coupon and confirm that you see the "Coupon code already applied!" message under the input field

3️⃣ Removing coupons

Staying on the shortcode

• remove all the currently applied coupons and confirm they are successfully removed

4️⃣ Other pages

• Repeat steps 2️⃣ and 3️⃣ on
  • Blocks checkout page
  • Cart block page
  • Shortcode cart page

5️⃣ Manual order creation & coupon management

• Create a new order in WooCommerce admin (WooCommerce → Orders → Add New)
• Add some products to the order
• Apply the VÅR20 coupon and confirm it's applied
• Remove the VÅR20 and confirm it's removed
• Apply the vÅr20 coupon and confirm case-insensitivity as the coupon should be applied too
• Apply the SummerSale2025 coupon and confirm it's applied
• Apply the SUMMERSALE2025 coupon and confirm that you see the "Coupon code already applied!" message under the input field
• Remove the coupons by clicking on the small "x" on the coupon icons and confirm the coupons are successfully removed

6️⃣ APIv1 tests

• Perform a POST /wp-json/wc/v1/coupons

{
  "code": "MÅQ25",
  "discount_type": "percent",
  "amount": "10",
  "individual_use": true,
  "exclude_sale_items": false,
  "minimum_amount": "100.00"
}

• Once the POST request is successful, please verify if you can use this coupon on any of the checkout or cart pages in different forms
  • MÅQ25
  • mÅq25

7️⃣ APIv2 tests

• Perform a POST /wp-json/wc/v2/coupons

{
  "code": "DÅQ25",
  "discount_type": "percent",
  "amount": "10",
  "individual_use": true,
  "exclude_sale_items": false,
  "minimum_amount": "100.00"
}

• Once the POST request is successful, please verify if you can use this coupon on any of the checkout or cart pages in different forms
  • DÅQ25
  • dÅq25

8️⃣ APIv3 order test

• perform aPOST /wp-json/wc/v3/orders request with a different case of a coupon included in the request body and confirm, that for all of them the request is successful

{
  "payment_method": "bacs",
  "payment_method_title": "Direct Bank Transfer",
  "set_paid": false,
  "billing": {
    "first_name": "John",
    "last_name": "Doe",
    "email": "admin@example.com"
  },
  "line_items": [
    {
      "product_id": 123,
      "quantity": 2
    }
  ],
  "coupon_lines": [
    {
      "code": "vÅR20"
    }
  ]
}

• Once the POST request is successful, check that the coupon is attached to the order in the order details

9️⃣ WooCommerce Analytics

• Navigate to Analytics -> Orders and confirm that the coupon codes are displayed for the orders they were used at
• Navigate to Analytics -> Coupons and confirm that the filtering/search of coupons works and is case-insensitive

Testing that has already taken place:

Changelog entry

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