Only 1 notification at a time on lock screen

Love this app but I only got 1 notification on lock screen no matter how many notifications that I received. Older ones will be replaced once new one comes in. I unchecked "compact mode" but it does not help. Any ideas?

[SimenCodes]

Hi!

Heads-up does only support one notification at a time at the moment. I was
planning to add support for more than one, but I don't have time to work on
the app these days, so I can't add that feature anytime soon (adding
multiple notifications is actually closer to making a completely new app
than changing the current one).

[cabrote]

multiple notifications is a must for this kind of app

[blueeagle69]

Agreed.
It sorely needs an option to show multiple notifications (like Android 5).