Subscription method

I am creating a react native project with GraphQL, and I want to use a subscription method to update the screen dynamically. There are two things I want to know:

  1. If the app is minimized for about 10 - 15 minutes (sample only), will the subscription method still works if the app becomes active?

  2. Is there a limit in the subscription method of GraphQL like in terms of the number of users?