+The names of configuration variables, and their default values and purposes,
+can change between release branches, e.g. $wgDisableUploads in 1.4 is replaced
+with $wgEnableUploads in later versions. When upgrading, consult the release
+notes to check for configuration changes which would alter the expected
+behaviour of MediaWiki.
+
+=== Check installed extensions ===
+
+Extensions usually need to be upgraded at the same time as the MediaWiki core.
+
+In MediaWiki 1.14 some extensions are migrated into the core. Please see the
+HISTORY section "Migrated extensions" and disable these extensions in your
+LocalSettings.php
+
+=== Test ===
+
+It makes sense to test your wiki immediately following any kind of maintenance
+procedure, and especially after upgrading; check that page views and edits work
+normally and that special pages continue to function, etc. and correct errors
+and quirks which reveal themselves.
+
+You should also test any extensions, and upgrade these if necessary.
+
+== Upgrading from 1.16 or earlier ==
+
+If you have a Chinese or Japanese wiki ($wgLanguageCode is set to one
+of "zh", "ja", or "yue") and you are using MySQL fulltext search, you
+will probably want to update the search index.
+
+In the "maintenance" directory, run the updateDoubleWidthSearch.php
+script. This will update the searchindex table for those pages that
+contain double-byte latin characters.
+
+== Upgrading from 1.8 or earlier ==
+
+MediaWiki 1.9 and later no longer keep default localized message text
+in the database; 'MediaWiki:'-namespace pages that do not exist in the
+database are simply transparently filled-in on demand.
+
+The upgrade process will delete any 'MediaWiki:' pages which are left
+in the default state (last edited by 'MediaWiki default'). This may
+take a few moments, similar to the old initial setup.
+
+Note that the large number of deletions may cause older edits to expire
+from the list on Special:Recentchanges, although the deletions themselves
+will be hidden by default. (Click "show bot edits" to list them.)
+
+See RELEASE-NOTES for more details about new and changed options.
+
+== Upgrading from 1.7 or earlier ==
+
+$wgDefaultUserOptions now contains all the defaults, not only overrides.
+If you're setting this as a complete array(), you may need to change it
+to set only specific items as recommended in DefaultSettings.php.
+
+== Upgrading from 1.6 or earlier ==
+
+$wgLocalTZoffset was in hours, it is now using minutes.
+
+== Upgrading from 1.5 or earlier ==
+
+Major changes have been made to the schema from 1.4.x. The updater
+has not been fully tested for all conditions, and might well break.
+
+On a large site, the schema update might take a long time. It might
+explode, or leave your database half-done or otherwise badly hurting.
+
+Among other changes, note that Latin-1 encoding (ISO-8859-1) is
+no longer supported. Latin-1 wikis will need to be upgraded to
+UTF-8; an experimental command-line upgrade helper script,
+'upgrade1_5.php', can do this -- run it prior to 'update.php' or
+the web upgrader.
+
+If you absolutely cannot make the UTF-8 upgrade work, you can try
+doing it by hand: dump your old database, convert the dump file
+using iconv as described here:
+http://portal.suse.com/sdb/en/2004/05/jbartsh_utf-8.html
+and then reimport it. You can also convert filenames using convmv,
+but note that the old directory hashes will no longer be valid,
+so you will also have to move them to new destinations.
+
+Message changes:
+* A number of additional UI messages have been changed from HTML to
+ wikitext, and will need to be manually fixed if customized.
+
+=== Configuration changes from 1.4.x: ===
+
+$wgDisableUploads has been replaced with $wgEnableUploads.
+
+$wgWhitelistAccount has been replaced by the 'createaccount' permission
+key in $wgGroupPermissions. To emulate the old effect of setting:
+ $wgWhitelistAccount['user'] = 0;
+set:
+ $wgGroupPermissions['*']['createaccount'] = false;
+
+$wgWhitelistEdit has been replaced by the 'edit' permission key.
+To emulate the old effect of setting:
+ $wgWhitelistEdit = true;
+set:
+ $wgGroupPermissions['*']['edit'] = false;
+
+If $wgWhitelistRead is set, you must also disable the 'read' permission
+for it to take affect on anonymous users:
+ $wgWhitelistRead = array( "Main Page", "Special:Userlogin" );
+ $wgGroupPermissions['*']['read'] = false;
+
+Note that you can disable/enable several other permissions by modifying
+this configuration array in your LocalSettings.php; see DefaultSettings.php
+for the complete default permission set.
+
+If using Memcached, you must enabled it differently now:
+ $wgUseMemCached = true;
+should be replaced with:
+ $wgMainCacheType = CACHE_MEMCACHED;
+
+== Upgrading from 1.4.2 or earlier ==