Why are all (that i tested) Lemmy Apps unable to send push notifications?

Hi,

I recently switched to lemmy from reddit. I tried some of the mobile apps, and for now decided to use Boost.

While testing i figured out, that non of the apps i tried out are able to send push notifications while the apps aren’t running. I have to open the app to recieve the notifications about e.g. new replies to my posts.

I am just curious: Is this a limitation of the lemmy software? Is this something that could be toggled by the instance hosts?