V128 notification mostly come via the windows notification center, so do you have them enabled there?

yes - I have the ALERTS setup to display the number of new emails on the task bar - AND also display a snippet of the incoming email..... the number is displayed - the snippet is not

It used to work fine prior to version 128 -

I had a similar issue on Mac OS when I upgraded to some version of Thunderbird or the OS or both, not sure.

The problem turned out to be caused by a bad hidden configuration setting that can only be found through Config Editor (at the bottom of the Settings > General window).

mail.biff.show_alert was false, don't ask me why, but setting it to true (default) solved the problem.

If your operating system is Windows 10: 1. Settings (of Windows 10) > System > Notifications & actions. 2. Under "Notifications", set "Get notifications from apps and other senders" to "On". 3. Under "Get notifications from these senders", click "Mozilla Thunderbird ESR", and set notifications to "On", and check at least one of "Show notification banners" and "Show notifications in action center".