Thread:Talk:Download/Class=mediawiki dont work correct/reply (3)

Downgrading to 1.18 would probably be fine. Downgrading to 1.8 probably won't work. Most schema changes are backwards compatible, but every now and then there are some that aren't (or that are only backwards compatible with limited efficiency like the categorylinks change).

The upgrade between 1.18 -> 1.19 involved the following schema changes: 200                        array( 'addIndex', 'logging',       'type_action',      'patch-logging-type-action-index.sql'), 201                        array( 'doMigrateUserOptions' ), 202                        array( 'dropField', 'user',         'user_options', 'patch-drop-user_options.sql' ), 203                        array( 'addField', 'revision',      'rev_sha1',         'patch-rev_sha1.sql' ), 204                        array( 'addField', 'archive',       'ar_sha1',          'patch-ar_sha1.sql' ), 205                        array( 'addIndex', 'page', 'page_redirect_namespace_len', 'patch-page_redirect_namespace_len.sql' ), 206                        array( 'modifyField', 'user_groups', 'ug_group', 'patch-ug_group-length-increase.sql' ), 207                        array( 'addField',      'uploadstash',  'us_chunk_inx',         'patch-uploadstash_chunk.sql' ), 208                        array( 'addfield', 'job',           'job_timestamp',    'patch-jobs-add-timestamp.sql' ), 209                        array( 'modifyField', 'user_former_groups', 'ufg_group', 'patch-ufg_group-length-increase.sql' ),

All of these should be backwards compatible with 1.18 (Although the user_options field was dropped, that hasn't been in use since like 1.15). Thus you should be able to just change your version of MediaWiki to 1.18 and everything would still work. However: The same is not true of MediaWiki 1.8, and I would be shocked if 1.8 worked with a 1.19 schema