diff -r 490d5cc509ed -r cf61fcea0001 wp/wp-admin/network/plugin-install.php
--- a/wp/wp-admin/network/plugin-install.php	Tue Jun 09 11:14:17 2015 +0000
+++ b/wp/wp-admin/network/plugin-install.php	Mon Oct 14 17:39:30 2019 +0200
@@ -13,7 +13,4 @@
 /** Load WordPress Administration Bootstrap */
 require_once( dirname( __FILE__ ) . '/admin.php' );
 
-if ( ! is_multisite() )
-	wp_die( __( 'Multisite support is not enabled.' ) );
-
 require( ABSPATH . 'wp-admin/plugin-install.php' );