Usual guide is: extract all files except ”/files” folder and ”/application/config” folder and update database by running updater script: index.php/updater
Detailed steps:
1. Download new version on codecanyon
2. in this downloaded zip file remove folders ”/files” and ”/application/config”
Example how to do that with 7zip archiver program:
Upload this file and extract on cpanel where script is installed
Upload via FTP is not suggested because sometimes files are skipped.
If you skipped some updates then check this old guide: https://iwinter.com.hr/support/?p=172
We can also provide updating services for additional cost, you can request via support ticket.