diff --git a/build/mediawiki_override/LocalSettings.php b/build/mediawiki_override/LocalSettings.php
index 9e4eab8..a66f879 100644
--- a/build/mediawiki_override/LocalSettings.php
+++ b/build/mediawiki_override/LocalSettings.php
@@ -60,6 +60,9 @@ $wgEmailAuthentication = true;
 // To enable image uploads, make sure the 'images' directory
 // is writable, then set this to true:
 $wgEnableUploads = true;
+$wgFileExtensions = array_merge($wgFileExtensions, [
+    'doc', 'xls', 'pdf', 'ppt', 'xlsx',
+]);
 // $wgUseImageMagick = true;
 // $wgImageMagickConvertCommand = "/usr/bin/convert";
 // $wgFileExtensions = [];