Firebase allows you to create different topics to which users can subscribe. Since Firebase is shared for all Push Notifications (such as the web, and also the BLOX Now App native application), the topics you create here will be available on both platforms. Thus, if you have already set up topics for your Now App, those same topics can be used for push notifications.
If you want to set up new topics, they will also become available on the BLOX Now App.
Note that the relationship between a user and a push notification topic is much less solid than with, for example, an email signup. Push notifications are simply a permission for a service to post a notification to the browser. Changing browsers or disabling a permission can completely erase a user’s tenuous connection to your messaging topics.
As such, changing the “topic ID” will disconnect all users who have allowed their browser to receive those topic notifications.