Eway Payment Gateway v5.0.0 is a big refactor with big changes: it requires PHP 7.4+, and WooCommerce 3.0+; it requires Eway Rapid API key / password; and the legacy XML API is no longer supported.
Update: 5.0.1 released to fix a crash when another plugin passes null to the filter hook
PHP 7.4+ and WooCommerce 3.0+
This release bids a goodbye to old versions of PHP and WooCommerce. It will now only run on websites with at least PHP 7.4 or later, and the WooCommerce integration requires at least version 3.0 of WooCommerce. If for some reason your website must run with older versions, then keep using version 4.5.1 of this plugin — but I strongly recommend upgrading everything to the latest versions if you can.
Rapid API key/password now required
Support for Eway’s legacy XML API has been removed. The plugin now requires a Rapid API key and password, and Client Side Encryption key. If your site doesn’t have those configured, please update them.
Eway credentials for filter hookers
If you hook some filters to modify Eway credentials, you will need to update your code to accept and return a Credentials object. If this means something to you, you will be able to find the class in the code and adapt your hooks to suit. If this means nothing to you, look away and maintain peace!
Customer payment page
When an order was created in the WooCommerce admin and a link emailed to the customer for payment, the customer payment page did not load the Eway encryption scripts. Now fixed.
You can update to the latest version from your WordPress plugin admin page. Here’s the full changelog for Eway Payment Gateway.