Firebase FCM Migration to New HTTPS Firebase

I've been utilizing Firebase Cloud Messaging (FCM) for push notifications in both my mobile and web applications. Now, I'm looking to migrate this FCM implementation to the new HTTPS Firebase.

Key Requirements:
- Migrate from existing Firebase Cloud Messaging to HTTPS Firebase.
- Ensure seamless functioning of the push notifications in both the mobile and web applications.

Ideal Skills and Experience:
- Extensive experience with Firebase Cloud Messaging.
- Proficiency in migration processes from legacy to new versions.
- Strong knowledge of HTTPS Firebase and its features.
- Previous work on both mobile and web applications.