Things you should know before upgrading to Jcow 10 from 9 or lower

Your old theme will not work with Jcow 10

Themes were upgraded for the purpose of cross devices. You need to re-edit your theme file based the new theme: themes/default .

Step 1

Upload the following files&folders to your sever and replace old files:
/upgrade.php
/fastquery.php
/files/common_css/style.css
/js/common.js
/modules/
/includes/libs/
/themes/default/*

Step 2

Run http://YOUR_JCOW_URL/upgrade.php from your browser to update database changes. And then delete upgrade.php from your server.

Step 3

Login as admin and go to Admin CP -> Modules, click "Update Modules".

done.