user to compare the current version with any older version. The difference engine is the same as the one used in MediaWiki. Parallel editing of one page by multiple users is prevented by a locking mechanism. Access control Access control can be handled by a user manager, which allows users and groups of users to be defined, and an access control list in which an administrator user can define permissions on page and namespace level, giving DokuWiki more fine-grained control than Mediawiki. Besides the built-in user management, DokuWiki also provides mechanisms for authentication against databases, LDAP Servers and Active Directory. Other authentication mechanisms are available as plugins. Plugins DokuWiki has a generic plugin interface which simplifies the process of writing and maintaining plugins. There are ~1000 plugins available. These can be easily integrated and managed by an administrator user with the help of the plugin manager. Templates The appearance of the wiki can be defined by a template. There are various templates provided by the development community. Internationalization and localization DokuWiki supports Unicode (UTF-8) and properly handles right-to-left languages, so languages such as Chinese, Thai, and Hebrew can be displayed. DokuWiki can be configured in about 70 languages. Multilingual wikis can be configured through plugins. Users can contribute translations of the DokuWiki software and of plugins through a web interface. Caching DokuWiki uses a two-level cache mechanism which stores the parsed wiki page in an intermediate serialized format which is then rendered to the desired output format, such as HTML5. This rendered format is cached again. The two levels of caching expire on different conditions. The caching helps to reduce server load and speeds up access to the information. Full text search DokuWiki has an integrated indexed search with which a user can search for keywords and phrases on the wiki. Wiki markup DokuWiki uses a simple markup language similar to that of MediaWiki. Like MediaWiki it makes use of free links, but CamelCase links can optionally be enabled. WYSIWYG editors are available as plugins. DokuWiki based software projects Some independent software projects based on DokuWiki have been created. These projects usually bundle the DokuWiki software, select plugins, a customized design and sometimes pre-built content for specialized use cases. The EinsatzleiterWiki is a German project, bundling fire fighting knowledge in a package that can be installed in fire departments and then be customized to the needs of the specific department.