404 after upgrading PHP to 8.1

I had installed invoice ninja 4.x almost 5 years ago in a namecheap cpanel shared hosting using .zip file upload method (and not via softaculous). It was working just fine until last month. I don’t remember updating invoice ninja’s version in the past days.

last month, our hosting account almost got banned due to email spoofing attacks. as the namecheap support suggested, I had to upgrade all existing pieces of software (PHP, wordpress etc) and took some other actions to avoid the ban on our hosting account.

I did not actually check if invoice ninja was running after taking the above mentioned actions. after passing some days, one of my team member reported me that invoice ninja is not working. It was showing a “Something went wrong” page with a 500 internal error. Then as namecheap support suggested, i tried downgrading PHP version and restore from their auto backup tool (both files and database) but in vain. It is at a current situation where the page is showing a 404 page powered by “Lightspeed web server”.

It would be great if someone could help me with restoring this instance. this instance has all our invoices for the last 5 years. Thanks in advance.


If you’re using v4 you’ll need to use PHP 7.x depending on the version.

To support PHP 8 you’d need to upgrade to v5.