Implement a dedicated Pub/Sub topic for each user to manage notifications. Deploy the application on Google App Engine's standard environment, which processes the predictions and sends notifications when a user's balance is predicted to drop below $25.

Utilize Firebase to construct a notification system. Register each user with a unique identifier in Firebase Cloud Messaging (FCM), configuring it to send notifications based on the average predicted balance of all users falling below $25.

Create a Pub/Sub topic for each user to handle notifications. Deploy a Cloud Function that triggers notifications when the model predicts a user's balance will drop below $25.

Build a notification system on Firebase, registering each user with a unique ID in Firebase Cloud Messaging (FCM). Configure FCM to send personalized notifications when the model predicts an individual's balance will drop below $25.

Combine the use of Firebase for user registration and notifications with Cloud Functions for processing predictions. Register each user in FCM and use a Cloud Function to analyze predictions and trigger FCM notifications for balances predicted below $25.