Only the most recent version of the plugin is supported. The current version can be found in the WordPress Plugin Directory: https://wordpress.org/plugins/wc-donation-platform/
If you found a security vulnerability in Donation Platform for WooCommerce, please contact wcdpATjonh.eu (replace AT with @). In return, I will do my best to respond to your email as soon as possible and fix the issue. You are also welcome to request a CVE for your find, e.g. at Wordfence, Patchstack or WPScan.