Thank you, I will try that out... also the plugin developer has provided this info below...
The research is in progress. There are some relatively many changes between two versions in both backend and frontend sides. I hope I’ll find something. Please be patient. But for now I have some more questions for you.
1. Please drop me here (or attach) your server’s System Info which could be found on the Sliced Invoices > Tools page. It possibly could be helpful for me as well to understand what’s happening.
2. Please check for any error in your Browser’s console and let me know if anything is present there (this gives us the information about frontend issues, conflicts, etc.)
3. Please make the following changes to your wp-config.php file:
4. Please turn on php error reporting.
5. Finally please try reproducing the errors again. Now your errors and warnings should be visible and logged. There could appear the /wp-content/debug.log file with your logged messages (if the directory is writable and if some errors are really there, otherwise no log file is created). Please send me those messages as well, if any.