I am posting here the first time but this platform help me a lot.
I see that many friends are getting errors while updating to v13.
and many people required a V13 OVA file
so I made a copy of the v13.14.0 production image here is the link
If any friend gets internal server error after restoring the image please follow the steps below.
edit mysqld.service file with any editor like nano
sudo nano /etc/systemd/system/mysqld.service
On the file change
and reboot VM
version of VirtualBox i Used v 6.1
erpnext v13.14.0 production image
ubuntu v 18.04