Mantis is an issue tracker that is implemented in php. the main features include:
* web based
* supports any platform that runs php
* available in 68 localizations
* customizable issue pages
* multiple projects per instance
* support for projects, sub-projects, and categories.
* users can have a different access level per project
* changelog support
* roadmap
* user view page
* search and filter
* built-in reporting (reports / graphs)
* time tracking
* custom fields
* email notifications
* users can monitor specific issues
* attachments
* issue change history
* rss feeds
* customizable issue workflow
* sponsorships support
* export to csv, microsoft excel, microsoft word
* no limit on the number of users, issues, or projects.
* public / private projects
* public / private notes
* public / private issues
* public / private news
* issue relationships
* authentication
+ default mantis authentication (recommended)
+ ldap integration
+ http basic authentication support
+ active directory integration (patches available)
* multi-dbms support (using adodb)
+ mysql
+ ms sql
+ postgresql
+ oracle (experimental)
* webservice (soap) interface
* and more