HOW TO UPDATE FROM v2.0, v2.1 or v2.2? 1. We DIDN'T changed database structure in v2.3. You can download new version and overwrite all files in "db/" directory from v2.0, v2.1 or v2.2
2. Changed or added files in v2.3 index.php admin.php actions_admin/settings.php actions_client/p.php config/*.* core/common.php core/pages.php lang/*.* plugins/tinymce/ - overwrite all files in this directory from newer version templates/default.css templates/admin/settings.tpl
If You want to update from Quick.Cms.Lite v2.2. Check changes using Total Commander. Select file in Quick.Cms.Lite v2.2 (first column) and the same file in Quick.Cms.Lite v2.3 (second column) and click in menu "Files" > "Compare by Content". You will find changes made by us.
If You want to update from Quick.Cms.Lite v2.1. First you must update to v2.2. Read this: http://opensolution.org/Quick.Cms/forum/?p=readTopic&nr=749