My pet peeve here is the Fastmail app in Android. It doesn't even open if there is no internet connection! Why? I'm pretty sure it caches already many mails locally, why doesn't it work?
Anyway, from the blog post:
> Calendar reminders will not show a notification.
This means that notifications are generated server-side and pushed to the device. I guess this is to...save battery? Wouldn't a background process work well enough, battery-wise?