PHPBack is described as 'Web application made with PHP/MySQL that you can easily implement into your website. It gives your customers a way to communicate their ideas to improve your products. User feedback has proved to be really effective even if you have a community project or a' and is a Help Desk platform in the business & commerce category. There are more than 10 alternatives to PHPBack for a variety of platforms, including Web-based, SaaS, Self-Hosted, Cloudron and Docker apps. The best PHPBack alternative is UserVoice. It's not free, so if you're looking for a free alternative, you could try UserReport or Astuto. Other great apps like PHPBack are Fider, UseResponse, Nolt and UserEcho.
Very clean interface and easy to setup via docker-compose. Albeit it doesn't support authentication via LDAP you can use any OAuth provider which asks a LDAP backend to get it working.