Hi Charles,
Not sure! Maybe Adalo Team can add some information about this that is this something coming in the future or already there? 
{ I’m sorry for tagging Adalo Team members. Interested to know about this 
: Jesse (@jessehaywood ), Patrick ( @pford ), Ben (@ben1 ) }
And this post by Victor also will help you! : How can I check if a user has allowed notification permission? - #2 by Victor
This topic will help too! : Way to see whether user accepted push notifications?
Thank you