Moving forward use upgrade from Cloud to avoid any issues during upgrade -> https://cyberpanel.net/docs/how-to-upgrade-your-cyberpanel-using-cyberpanel-cloud/
For people with issues related to upgrade. (Mostly related to emails).
You can contact us through -> https://cloud.cyberpanel.net/
And do mention that your email services stopped working after upgrade. We will then enable Cloud Email Debugger in your account, using which you can reset your email configurations to default. It will also check and fix all SSL related issues on your email server.
Have a good day.