Main Dokuwiki page:
[[https://www.dokuwiki.org/dokuwiki]]

Downloading Dokuwiki:
[[http://www.splitbrain.org/projects/dokuwiki]]

Upgrading Dokuwiki:
[[https://www.dokuwiki.org/install:upgrade]]

Upgrading can also be done very easily via the upgrade plugin, available via the Admin page once you are logged in.