Thread:Extension talk:Semantic MediaWiki/Cannot install core SMW2.0 extension on MW1.23

Hello, I'm trying to install just SMW by itself on MW1.23.5 but when I use either composer or the ExtensionDistributor I get the same result when trying to run the maintenance/update.php script which is about 15 warnings about classes such as "SMW\Store" not found and finally a fatal error as follows:
 * Fatal error: Class 'SMW\SimpleDependencyBuilder' not found in /home/translat/public_html/w/123/mediawiki-1.23.5/extensions/SemanticMediaWiki/SemanticMediaWiki.php on line 112

Anyone have any ideas what might be wrong here?