The Phase II software, or the PHP script, was the precursor to MediaWiki written by Magnus Manske and replaced the UseModWiki engine on the English Wikipedia on 25 January 2002. It was replaced by MediaWiki (also known as the Phase III software) on the English Wikipedia on 20 July 2002.
See:
- Wikipedia:Phase II feature requests
- Wikipedia:Phase II bug reports
- Wikipedia:MediaWiki (archive)#History
- Wikipedia:MediaWiki (archive)#Change from Phase II to Phase III
- Wikipedia:MediaWiki FAQ, much of which deals with the Phase II software (also see the version from May 2002)