* Feature - Allow customers to choose the amount of credit to purchase.

* Tweak - Display the credit amount when a Store Credit product is added to the cart.

* Tweak - Updated the 'Store Credit' description text on the 'My Account' page.

* Tweak - Tested compatibility up to WC 6.3.

* Tweak - Tested compatibility with WP 5.9.

* Dev - Use a WC background process to handle the plugin updates.

* Dev - Use a trait instead of a class for implementing the Singleton pattern.

* Dev - Dropped deprecated plugin code up to version 3.9.

* Dev - Removed deprecated constants `WC_STORE_CREDIT_PLUS_VERSION`, `WC_STORE_CREDIT_PLUGIN_DIR`, and `WC_STORE_CREDIT_PLUGIN_URL`.

* Dev - Updated the minimum requirements to WC 3.7, WP 4.9, and PHP 5.6.

* Feature - Added setting to edit the title to Send to someone of Store Credit products.

* Tweak - Tested compatibility with WC 6.0.

* Tweak - Tested compatibility with WC 5.9.

* Tweak - Improved the distribution of the coupon credit over the cart items.

* Fix - Fixed wrong discount when the cart contains many low-priced items.

* Tweak - Tested compatibility up to WC 5.8.

* Fix - Fixed warning caused by the undefined variable `$found`.

* Tweak - Tested compatibility with WC 5.6.

* Fix - The credit is not updated when passing a coupon code to the function `wc_update_store_credit_used_for_order`.

* Feature - Added compatibility with the extension 'WooCommerce PayPal payments'.

* Tweak - Recover the credit used in the order awaiting payment when proceeding to its purchase.

* Tweak - Update the cart session after applying a discount to the shipping costs.

* Tweak - Tested compatibility up to WC 5.5.

* Tweak - Tested compatibility with WP 5.8.