If you are coming from a version earlier than the 01 May 2000 production release, please see 
TWikiUpgradeTo01May2000 first.
These are the steps you need to perform to upgrade the 01 May 2000 version to the current Beta version: [ We assume 
export TWIKIROOT=/some/dir/
-  Unpack the beta zip file into some working directory:
 
  mkdir -p ~/tmp/
  cd ~/tmp
  unzip ~/TWiki20000818beta.zip
-  Merge and changes in your current wikicfg.pm into the new 
wikicfg.pm.  We suggest using diff -c to compared the two files if you have made heavy changes to the file:
 
   diff -c wikicfg.pm $TWIKIROOT/bin/wikicfg.pm | less
-  Create and populate the TWiki directory below the data directory.
 
  cd $TWIKIROOT/data/
  mkdir TWiki
  cp ~/tmp/data/TWiki/* TWiki/
-  Delete the following files in your TWiki.Main installation:
-  
BillClinton , GoodStyle , RegularExpression , TextFormattingFAQ , TextFormattingRules , TWikiAdministration , TWikiCategoryTable , TWikiDocumentation , TWikiEnhancementRequests , TWikiHistory , TWikiImplementationNotes , TWikiInstallationNotes , TWikiNotificationOfChanges , TWikiPlannedFeatures , TWikiPreferences , TWikiUpgradeTo01May2000 , TWikiUsernameVsLoginUsername , TWikiVariables , TWikiWeb , WelcomeGuest , WikiName , WikiNotation , WikiTopic , WikiWikiClones
 
 
  cd $TWIKIROOT/data/Main
  rm -f BillClinton* GoodStyle* RegularExpression* TextFormattingFAQ*       TextFormattingRules* TWikiAdministration=* TWikiCategoryTable*        TWikiDocumentation* TWikiEnhancementRequests* TWikiHistory*       TWikiImplementationNotes TWikiInstallationNotes* TWikiNotificationOfChanges*       TWikiPlannedFeatures* TWikiPreferences* TWikiUpgradeTo01May2000*        TWikiUsernameVsLoginUsername* TWikiVariables* TWikiWeb* WelcomeGuest*       WikiName* WikiNotation* WikiTopic* WikiWikiClones*
-  In all your webs, change references to topics that moved to the TWiki.TWiki web:
-  Change topics: 
TWikiUsers , WebNotify , WebHome
 
-  With links to: 
TWikiPreferences , TWikiVariables , TWikiUsers , TWikiWebsTable , WelcomeGuest
 
 
-  Move your 
TWikiWebsTable topic to TWiki.TWiki.
 
-  Merge your changes to 
TWikiPreferences into TWiki.TWikiPreferences , then delete Main.TWikiPreferences
 
-  In case you customized 
TWikiRegistration , merge your changes back into TWiki.TWikiRegistration , then delete Main.TWikiRegistration .
 
-  In case you have authentication: Change 
.htaccess to reflect the new location of the TWikiRegistration , i.e. 
 ErrorDocument 401 /cgi-bin/view/TWiki/TWikiRegistration
 
-- 
PeterThoeny? - 20 Aug 2000