The update process is really simple
1. Backup your MySQL Database
2. Backup your files
3. Remove from folder where the ClientExec installation is located all except config.php and uploads/ folder
4. Download the latest version from https://www.clientexec.com/download.php?fuse=files&view=FileList
5. Place all files from zip except config.php and uploads/ folder into your ClientExec directory
6. To start update run http://yoursite.com/yourclientexecpath/install.php
7. Login using your ClientExec email/username and password
8. Agree to the end-user license agreement
9. Choose to continue
10. Check the box stating that you have created a backup of your database and click "Continue"