X-Notifier 3 works FINE! Rated 5 out of 5 stars

X-Notifier v3 works great. However, the upgrade from 2.x.x may not work well for everyone. If you're having problems, rather than insult the addon, try UNinstalling it (and delete user data), then re-install and rebuild accounts FROM SCRATCH. (do NOT import accounts). Yes, sh*tuff happens. If you don't get a good update for this significant version, then start fresh. Version 3 works VERY well for thousands of us.

This review is for a previous version of the add-on (3.0).  This user has other reviews of this add-on.