• There have been three phases of the software so far: [1]
  • Phase I (starting 2001-01-15): UseMod wiki
  • Phase II (starting 2002-01-25): custom PHP
    • User:Conversion script started converting pages over from the UseMod format to PhaseII. It later managed to recreate some of the original history as well. [2] [3]
  • Phase III (starting 2002-07-20): MediaWiki (PHP)
  • Phase III.x: MediaWiki roadmap
• nostalgia.wikipedia.org contains a very old snapshot of the wiki's data (the homepage identifies it as from December 20, 2001). Although this is Phase I content, the software it runs appears is Phase III (as far as I can tell, it's kept up to date with Wikipedia's software)
  • User:Conversion_script says it only ran in 2005... but it made some interesting changes... [4]. I assume this is a separate run of Conversion_script than originally occured on Wikipedia (so it may be more accurate, because it uses the script's latest code? At the least, it jumped straight from Phase1⇒3)
  • Building Wikipedia membership