Bug fixes included in this version: http://opensolution.org/download/Quick.Cart/bugFixes.txt
HOW TO UPDATE DATABASE FROM v4.1? 1. We DIDN'T changed database structure in v4.2. You can download new version and overwrite all files in "db/" directory from v4.1
If You want to update from Quick.Cart v4.1. Check changes using Total Commander. Select file in Quick.Cart v4.1 (first column) and the same file in Quick.Cart v4.2 (second column) and click in menu "Files" > "Compare by Content". You will find changes made by us.