The MediaWiki version compatibility (VC) for iSC Inc. wikis.
Add to the LocalSettings.php:
require_once( "$IP/extensions/v1.24/V/VC/versioncompatibility.php" );
Add to your extension:
if ( version_compare( $wgVersion, '1.24', '<' ) ) {
die( "This iSC Inc. extension requires MediaWiki 1.24+\n" );
}